# MCAT Physics 2 Flashcards

Terms Definitions
 U Fdelta F/q E= power energy/second centripetal acceleration v^2/r Lens equation 1/id+1/od=1/f Voltage (V=) W/q, (kq)/rq weight mass * gravity Pascal (Pa), N/m² Pressure units= Forces cancel Transitional equilibrium when Velocity @ constant a Vf=Vi+at What are virtual images? Equations for perfectly inelastic collisions m1vi=(m1+m2)vf v²/r Magnitude of centripetal acc, ac Is light wave or particle? both Work eq. for a spring W=1/2Kxsquared Temperature increases Coefficient of surface tension decreases as? Gauge Pressure Pressure above the atmospheric pressure, given only by ρgz; the difference between P(absolute) and P₀ d=vot + ½at2 Big 5 missing v mirror-lens equation 1/o + 1/i = 1/f torque force that causes rotation   Τ  = rFsinθ Greater Pressure is lower where flow speed is? Force Vector quantity describing the push or pull on an object. SI unit for force is the Newton, N. ________ is the magnitude of the velocity. Speed formula for acceleration a=change in velocity/time...any change in velocity (either magnitude or direction) is acceleration, a particle must accelerate to change the direction of its motion, velocity and acceleration don't have to be in the same direction Streamline Flow smooth, well-behaved flow, where the flow velocity at any point remains constant what are the main 3 trig functions S=OHC=AHT=OA beta+ decay A stays the same Z-1   (ß+ = positron) What are the image characteristics of an object located in front of F in a concave mirror? doppler v/c = deltaf / f(source), delta lambda / lambda(source Is the anode always the site of oxidation? Yes RMS Current Quantity used to calculate the average dissipated in an AC circuit, given by I(max)/(√2). Must be used because the average current, when calculated conventionally, equals zero as a result of the periodic nature of that current. If two projectiles leave the earth with the same vertical velocity, they will land at the... same time. virtual image image from which light rays only appear to diverge virtual images are always upright Work (W) Force (F) * Distance (d) * cos Θ photoelectric effect energy of emitted electron is the energy of the incident light minus work function of hte metal   KE = hv - W   W = hv0 What are projectiles? •Projectiles are free falling bodies that is shot, thrown, or in some other way launched into the air. The motion or trajectory of a projectile is a parabola. A projectile motion consists of two independent parts: 1) Vertical motion at a constant downward acceleration toward the Earth, which is equal to a = -g = -9.80 m/s^2. 2) Horizontal motion at a constant horizontal speed, v = constant. The vertical acceleration of g toward the Earth holds true at all times, even when the projectile is traveling up (it's decelerating on its way up, which is the same thing as accelerating down). Gravity cannot change the object's horizontal speed, and the component of the object's horizontal velocity remains constant throughout its motion. There is no acceleration in the horizontal component. The object's vertical motion is the same as that of an object undergoing only vertical free-fall. Gravity only affects the object's vertical motion. When you toss something straight up and it comes down to where it started, the displacement, s, for the entire trip is 0. Also, initial velocity and acceleration are opposite in sign and Initial velocity and final velocity are equal and opposite. For this, time spent going up = time spent coming down. All horizontal motion has zero net force and no acceleration, but has constant velocity. The reason is that acceleration only acts in the downward direction. The peak height can be found with: vsinΘ = square root of (2gh) A projectile exhibits symmetry: its path upward is the mirror image to its path downward. This means that for a projectile over a flat plane, time is the same for both halves of the flight and the initial speed is equal to the final speed. What are projectiles? Masses are irrelevant in projectile paths. lines of force lines that travel from + to - Completely Elastic Collision Type of collision in which both momentum and kinetic energy are conserved. The sum of initial and final kinetic energies in a collision are equal. (initial) m₁v₁ + m₂v₂ = (final) m₁v₁ + m₂v₂ Momentum Often denoted as p, it is a vector quantity, as the product of an object's mass and velocity. p = mv No Does free fall acc of an object depend on its mass? Streamline a line in a flow tube which is everywhere parallel to the direction of fluid flow at a particular instant Vector or Scalar: distance, speed, displacement, mass, velocity, force, acceleration, energy Pressure, mass distance=s, speed-s, displacement=v, mass=v, velocity=v, force=v, acceleration=v, energy=s, Pressure=s, mass=s How do you resolve a vector to Cartesian x-coordinates? This formula What are longitudinal waves? In longitudinal waves the displacement of the medium is parallel to the propagation of the wave. So the displacement is left and right and the propagation (velocity) of the wave is left and right. A wave in a "slinky" is a good visualization because the slinky moves to the left and right and that is also how the velocity of the slinky is moving - meaning everything is moving in a parallel direction. Sound waves in air are longitudinal waves. Pressure waves and earthquakes are other examples. (EA/Lo)=k and ∆L= x F=[(EA/Lo) x ∆L which equals F=kx for a spring so... Doppler Effect When a source emitting a sound and a detector receiving the sound move relative to each other, the virtual frequency vf' detected is less than (distance increases) or greater (distance decreases) than the actual emitted frequency. f' = f(V±V(d))/(V±Vs) m1v1 + m2v2 = (m1 + m2)v' Perfectly inelastic collision equation? How do pulley's reduce work? reduce force necessary by increasing distance travelled What are beat frequencies? ◦Beats occur when two waves coexist at different frequencies. ◦The beat frequency is the difference between the frequencies of the two waves. When two sound waves of different frequency approach your ear, the alternating constructive and destructive interference causes the sound to be alternatively soft and loud - a phenomenon which is called "beating" or producing beats. The beat frequency is equal to the absolute value of the difference in frequency of the two waves. A special case of superposition of waves is the phenomenon known as beats. Beats occur when two waves with slightly different frequencies are superimposed. At some points they will be nearly in phase and experience constructive interference. At other points they will be out of phase and experience destructive interference. These points will alternate with a frequency equal to the difference between the frequencies of the original two waves. This difference is called the beat frequency. What are thin films? ◦Thin films provide a means for interference to occur. ■Light reflecting off the outer and inner boundary of a thin film interfere with each other. ■A film of oil on water has the appearance of a swirly rainbow due to this interference. Interference between light waves is the reason that thin films, such as soap bubbles, show colorful patterns. This is known as thin-film interference, because it is the interference of light waves reflecting off the top surface of a film with the waves reflecting from the bottom surface. To obtain a nice colored pattern, the thickness of the film has to be similar to the wavelength of light. Electric potential (definition) the amount of work required to move a positive test charge Greater theforce of kinetic friction the greater the, uk, coefficient of kinetic friction the Describe the force on a charge in a magnetic field F = qvBsinθ What are standing waves? A standing wave, also known as a stationary wave, is a wave that remains in a constant position. This phenomenon can occur because the medium is moving in the opposite direction to the wave, or it can arise in a stationary medium as a result of interference between two waves traveling in opposite directions. In the second case, for waves of equal amplitude traveling in opposing directions, there is on average no net propagation of energy. The sum of two counter-propagating waves (of equal amplitude and frequency) creates a standing wave. Standing waves commonly arise when a boundary blocks further propagation of the wave, thus causing wave reflection, and therefore introducing a counter-propagating wave. For example when a violin string is displaced, longitudinal waves propagate out to where the string is held in place at the bridge and the "nut", whereupon the waves are reflected back. At the bridge and nut, the two opposed waves are in antiphase and cancel each other, producing a node. Halfway between two nodes there is an antinode, where the two counter-propagating waves enhance each other maximally. There is on average no net propagation of energy. P1 + (1/2)ρv² + ρgy1 = P2 + (1/2)ρv² + ρgy2 Bernouli's Equation, pg 179 buoyant force, B B= net upward exerted by a fluid on an object What happens when a charged particle moves perpendicular to a magnetic field? Has constant circular motion where centripetal force = magnetic force   F = qvB = mv2/r Explain the fact that Amount of work done in gravitational field is path-independent. ◦Unlike friction, gravity always acts downwards. The gravitational force is path-independent. Thus, force perpendicular to the gravitational force involves no work. The force exerted by the person is an upward force equal to the weight of the box, and that force is perpendicular to the motion. Since the force exerted on the object is up and down, but is not in the direction of the motion (which is to the right or left), the work is 0. Put it another way, W = Fdcosθ, but here cosθ = cos90 = 0. Pushing an object at constant speed up a frictionless inclined plane involves the same amount of work as directly lifting the same object to the same height at constant speed. ◦Sliding down a frictionless inclined plane involves the same gravitational work as doing a free fall at the same height. As long as the distances are equal, the work is equal. Why? Because work done BY GRAVITY is always the same: W = mgh. It doesn't matter how it goes down, down a frictionless slide, free fall, swing, whatever, if we are calculating work done BY GRAVITY, then W = mgh. Also, with the same example, if we have three objects with the same mass that slides down a frictionless incline, does a free fall, swings, etc from the same height and move down the same vertical distance, these same objects have the same amount of net work done on it by gravity and they have the same velocity at the bottom of the path because their work equals the change in KE, which is 1/2mv^2 and because their mass is the same, their velocity is the same. Now, usually, questions ask about work done ON AN OBJECT - and that's a different story. Work done on an object is W = Fdcosθ. Work done on an object could mean there are different forces added. If the only force acting on the object is gravity, then the work done would be by the gravity force. However, the difference between W = mgh and W = Fdcosθ is h and d. H is used if we know the height of the incline. D is used if we know the length of the incline. The significance of work done by gravity is that it is from a certain HEIGHT, not LENGTH. Explain the fact that Amount of work done in gravitational field is path-independent. Work due to gravity is W = mgh. Work due to friction force is W = (Force of friction)(distance that the object travels). The distance that the object travels is not height, like with gravity, it is the length. What is the difference between the electrostatic and electromagnetic force? The attractive force between the electrons and the nucleus is called the electrostatic force (electric force). Experiments have shown that the electric force between two objects is proportional to the inverse square of the distance between the two objects. The electric force between two electrons is the same as the electric force between two protons when they are placed as the same distance. This implies that the electric force does not depend on the mass of the particle. Instead, it depends on a new quantity: the electric charge. The unit of electric charge q is the Coulomb (C). The electric charge can be negative, zero, or positive. The precise magnitude of the electric force that a charged particle exerts on another is given by Coulomb's law: kq1q1/r^2. Measurements of the velocity of the orbital electrons in an atom have shown that the attractive force between the electrons and the nucleus is significantly stronger than the gravitational force between these two objects. An important difference between the electric force and the gravitational force is that the gravitational force is always attractive, while the electric force can be repulsive (Fc > 0), zero, or attractive (Fc < 0), depending on the charges of the particles, where Fc is the electric force. The electric force exerted under circumstances in which the charges are at REST or are moving very slowly is the electrostatic force. On a microscopic scale, the electric force dominates the gravitational force, but on a macroscopic scale, the gravitational force dominates. Since most macroscopic objects are neutral, they have an equal number of protons and electrons. The attractive force between the electrons in one body and the protons in the other body is exactly canceled by the repulsive force between the electrons in the two bodies. If the charges are MOVING with a uniform velocity, they will experience both the electrostatic force and a magnetic force. The combined electrostatic and magnetic force is called the electromagnetic force. So the electromagnetic force comes into play when the charges are moving, while the electrostatic force comes into play when the charges are at rest. Electromagnetic forces can come into play with different molecules like the molecules of hand and of other objects, when the both come into contact with each other. With electrostatic forces, the forces can occur even when the charges are still "static", while with magnetic forces, the charges have to be in motion. k(q/r²) where r is the distance from charge to a specific point E (electric field)= units of N/C Towards the center of the circle, also denoted as centripetal In uniform circular motion what direction is the acc in? What are the three SI units for mechanics? 1. meter 2. kilogram 3. second What is the definition of rate constant? In chemical kinetics a reaction rate constant k quantifies the speed of a chemical reaction. To find velocity before impact of one-dimension Use problem v=Vo +at (a= 10m/s2, t= time, Vo=initial velocity) In these cases Vo is always 0 unless directed otherwise Give Prefix and abbreviation for powers of ten (9, 6, 3, -2, -3, -6, -9, -12) Giga (G or B), Mega (M), Kilo (K), Centi (c), Milli (m), Micro (u), Nano (n), Pico (p) What is Newton’s third law (forces equal and opposite)? Every action has a reaction equal in magnitude and opposite in direction. Say you have a continent of mass m collides with another continent of mass m/2 that is initially at rest. During the collision, the more massive continent is found to exert a force F on the less massive continent, causing the smaller continent to accelerate. At the same time, the less massive continent exerts a force on the larger continent of a magnitude F. Newton's third law requires that mutual forces exerted between these two continent collisions (or any collision) be equal in magnitude. The smaller continent accelerates because it exerted a force F on the larger continent, but the larger continent has a greater mass, so it doesn't accelerate like the smaller continent. It is essential to understand that the reaction applies to another body that the one on which the action itself applies. For instance, in the context of gravitation, when object A attracts object B (action), then object B simultaneously attracts object A (with the same intensity and an opposite direction). Another important point to keep in mind is that the physical nature of the reaction force is identical to that of the action itself: if the action is due to gravity, the reaction is also due to gravity. Since a force by an object produces a reactionary force on an object, the reactionary force exerted on an object has a negative acceleration, which means that it exerts a negative velocity and negative speed on the object - which slows the object that exerted the force down. If an object has density = 250 kg/m^3, then what percentage of the object will float above the surface of water? Ratio of densities of object:water = 0.25 : 1 --> 25% of the object will SINK, and 75% of the object will float above the surface of water When is there no force on a charge in a magnetic field? When charge moves parallel or antiparallel to magnetic field How does Young's Double slit experiment prove light is a wave? We set up our screen and shine a bunch of monochromatic light onto it. If light is a wave: There are still only two light rays that actually go through the slits, but as soon as they pass through they start to diffract. We must conclude that light is made up of waves, since particles can not diffract. Young's double slit experiment showed constructive and destructive interference by monochromatic light passing through two slits creating two coherent waves by diffraction with constant phase difference, due to they are coming from the same source. This interference can then be seen by projecting the light onto a piece of paper showing "Fringes" where a bright band is constructive interference and a dark band is destructive interference. Can there be power if there is zero current or zero voltage? In an open circuit, where voltage is present between the terminals of the source and there is zero current, there is zero power dissipated, no matter how great that voltage may be. Since P=IV and I=0 and anything multiplied by zero is zero, the power dissipated in any open circuit must be zero. Likewise, if we were to have a short circuit constructed of a loop of superconducting wire (absolutely zero resistance), we could have a condition of current in the loop with zero voltage, and likewise no power would be dissipated. Since P=IV and V=0 and anything multiplied by zero is zero, the power dissipated in a superconducting loop must be zero. How do you find an object with linear motion's velocity? v =  v0 + at   v2 = v02 + 2aΔx y1−y2 D= Fc=mv2/r Kilo? 10^3 rFsin(theta) Torque (τ)= Av Flow rate f= Ei + WbyF Ef= Linear Distance x = rθ (v₀x)t Projectile motion displacement: x= Snell's law n1sinθ1 = n2sinθ2 What are axis-vector components? Increases Tube narrows then flow speed? v₀x (constant) Projectile motion velocity: vx= Hooke's Law F = -kx PE= ½kx² vector has both magnitude and direction Equilibrium • no translational or rotational acceleration ---> constant velocity Static Equilibrium: all velocities = 0 Dynamic Equilibrium: velocities ≠ 0 Dielectric Insulating material placed between the two plates of a capacitor. If the circuit is plugged into a current source, more charge will be stored in the capacitor. If the circuit is not plugged into a current source, the voltage of the capacitor will decrease. Yes Is the direction of acceleration always the same as Fnet? Wtotal = ∆KE The Work-Energy Theorum is? frequency  of light E = hv   c = λv Translational Equilibrium • any system in translational eq.: upward forces = downward forces & rightward forces = leftward forces ∴ net force = 0 Conductor Material in which electrons can move with relative ease. Magnification Dimensionless value denoted by m given by the equation: m = -i/o, where i is image height and o is object height. A negative m denotes an inverted image, whereas a positive m denotes an upright image. Sir Isaac ________ was an English scientist whose treatise Philosophiae Naturalis Principia Mathematica, published in 1687, described universal gravitation and the three laws of motion. Newton Work is negative If theta was 90 theta_critical Right Hand Rule Common method used to determine the direction of the magnetic force vector. Thumb points in the direction of charge's velocity, fingers point in direction of magnetic (B) field, palm points in the direction of the acting force. Daniel Burnham Make no little plans. They have no magic to stir men's blood and probably themselves will not be realized. Make big plans; aim high in hope and work, remembering that a noble, logical diagram once recorded will never die, but long after we are gone will be a living thing, asserting itself with ever-growing insistency. Remember that our sons and grandsons are going to do things that would stagger us. Let your watchword be order and your beacon beauty. Think big Fluid A fluid is a substance that can flow; it cannot withstand a shear stress. Liquids and gases are fluids What happen to the frequency when a wave crosses from one medium to another stays constant Doppler effect when there is relative motion btwn a sourceof a wave and an observer, the frequency of vibrations received by the observer increases if the source and observer approach one another and decreses when they seperate What is pascal's law? ◦Pascal's law: if you apply pressure on a liquid, the pressure is transmitted equally to all parts of the liquid. P = F/A and the unit is in Pascals: N/(m^2). The pressure is the same at a given depth. If pressure wasn't the same, then the fluid would flow to the lower depth and equalize. The hydraulic press is one of the most important applications of Pascal's law. With this device, one may multiply forces to almost any desired degree. The apparatus consists essentially of a large and a small piston, each within cylinders connected at the base. The whole vessel is filled with fluid. When a pressure is applied to the small piston, this pressure is transmitted through the fluid and acts on the large piston. If the pistons are at the same height, the pressure on each will be equal, so the force upon each will be directly proportional to their respective areas: F1/A1 =F2/A2. The pressure input at one end is the same as the pressure output at the other. You apply a small force over a small area, and the output force at the end with the larger area will be greater. A1d1=A2d2, where d is the distance that the end moves. The work done on one end is the same as the work output at the other. Because the volume of fluid pushed down on the left side equals the volume of fluid that is lifted up on the right side, the following formula is also true: V1 = V2 by substitution: A1d1 = A2d2. Volume is equal to area * distance (cubic meters). If we increase the pressure on one of the surfaces enclosing a fluid, this increase will be transmitted undiminished to all parts of the fluid. The number of times a hydraulic press multiplies the force applied to it is called its mechanical advantage or force ratio. So, for example, a hydraulic press with 100 N exerted over 1 m^2 can hold up to 400 N exerted over 4 m^2. The Pascal is also kg/(m*s^2) What is pascal's law? Also, because ideal machines like hydraulic lifts do not change work, the distance through which the force is applied is inversely proportional to the force, or F1d1 = F2d2. PRESSURE ONLY DEPENDS ON DEPTH. With these problems, and any questions about area, the pressure is always the same. It doesn't matter how different the areas are, as long as the depth is the same, the pressure is the same. So basically, these variable is the FORCE output. The force and area can be different, but the pressure is the same (at the same depth)! Inclined Planes - Force due to gravity and the normal force of an inclined plane = mgsinθ for any inclined plane and points directly along the plane Heat of Transformation Amount of heat required to change the phase of a substance, calculated by (substance mass)*(substance's heat of transformation) q = mL. the vector from pivot point to point of force application Radius vector, r? SI unit for Work and Energy Joule (J) which equals (N/m) What is uniform circular motion? Uniform circular motion describes the motion of a body traversing a circular path at constant speed. The distance of the body from the axis of rotation remains constant at all times. Though the body's speed is constant, its velocity is not constant: velocity, a vector quantity, depends on both the body's speed and its direction of travel. This changing velocity indicates the presence of an acceleration; this centripetal acceleration is of constant magnitude and directed at all times towards the axis of rotation. This acceleration is, in turn, produced by a centripetal force which is also constant in magnitude and directed towards the axis of rotation. Because the velocity v is tangent to the circular path, no two velocities point in the same direction. Although the object has a constant speed, its direction is always changing. This change in velocity is caused by an acceleration a, whose magnitude is (like that of the velocity) held constant, but whose direction also is always changing. Acceleration is perpendicular to velocity. What is Torque? The lever arm is defined as the perpendicular distance from the axis of rotation to the line of action of the force. The lever arm does not necessarily equal the wrench, or whatever straight object we are referring to. It can be perpendicular to the force applied to the object in space. Note that it's the LINE OF ACTION of the force - the lever arm and the force don't necessarily have to be in the same direction, meaning the lever arm and force doesn't have to touch at right angles, but the lever arm has to make a right angle with the line of action of the force. ◦Torque is the angular equivalent of a force - it makes things rotate, have angular acceleration, change angular velocity and direction. The axis of rotation is where on the object the rotating (twisting) is taking place. The convention is that positive torque makes things rotate anticlockwise and negative torque makes things rotate clockwise. Torque can be solved with respect to the lever arm OR with respect to the radius of of object to the point of force : Torque = rFsinθ. When you have a problem that does NOT imply there is a fulcrum, instead, you have a board that is held up by a rope and also has 1 mass (or more) hanging from it - it is an equilibrium question. Basically, first analyze what the regular forces are - the forces that are up (usually the tension from the rope) and the forces that are down (usually the weight of the mass(es) and the board). Then use that equation to figure out the counterclockwise and clockwise torques. But here, since we don't have a designated fulcrum, we can pick our fulcrum anywhere we want (where the rope is is not necessarily where the fulcrum is). The easiest way to do this is to pick the fulcrum (point of rotation) to be at the end of the board. Then, when figuring out the torque, use the distance as the distance of the mass(es), rope, and center of gravity of the board from the end of the board. Don't forget that the board uses the center of gravity to find the distance from the fulcrum when calculating the torque - that is where the mass is concentrated for the board. To increase the focusing power of the eye, how is the lens changed? Increased curvature of lens Newton's 2nd law F=ma, or a force is proportional to an applied acceleration; no acceleration means no force What are the formulas for the initial horizontal and vertical velocities of a projectile launched with speed v at an angle of theta to the horizontal? Horizontal velocity= v(cos theta)Vertical velocity = V(sin theta) What are Neutrons, protons, and isotopes? •Neutrons = neutral particles that reside in the nucleus. •Protons = positive particles that reside in the nucleus. •Isotopes = things with the same number of protons, but different number of neutrons. •Nucleons = protons or neutrons. •Isotopes often have similar chemical properties, but different stabilities (some decay and give off radiation, some don't). Newtons 2nd law - when an object is acted upon by a net force, the change in that objects motion will be inversely proportional to the mass (m) of the object and directly proportional to the net force (F) F = ma How the object's mass is distributed with respect to the axis it rotates around What does rotational inertia depend upon? Give Cos value for the following angles: 0, 30, 45, 60, 90, 180 1, !3/2=0.87, !2/2=0.7, 1/2, 0, -1 What is Simple harmonic motion; displacement as a sinusoidal function of time? The motion is periodic: the body oscillates about an equilibrium position in a sinusoidal pattern in the vertical motion. Each oscillation is identical, and thus the period, frequency, and amplitude of the motion are constant. y = A·sin(ωt). y is displacement (y-axis). For transverse waves, the y-axis gives the transverse displacement, the displacement of the medium perpendicular to the direction of propagation. For longitudinal waves, the y axis may either be pressure or displacement of the medium parallel to the direction of propagation. The x-axis is time. A is amplitude. ω is angular frequency in radians (also called angular velocity). t is time. Examples of simple harmonic motion: Oscillating spring, Pendulum, and Things going around a circle at constant speed (If we consider just the y-component of the motion the path with time we can see that it traces out a wave). Simple harmonic motion can in some cases be considered to be the one-dimensional projection of uniform circular motion. If an object moves with angular velocity ω around a circle of radius r centered at the origin of the x-y plane, then its motion along each coordinate is simple harmonic motion with amplitude r and angular frequency ω. Simple harmonic motion means that it is a sinusoidal function in time. What is Simple harmonic motion; displacement as a sinusoidal function of time? Two important properties of simple harmonic motion: The acceleration is directly proportional to the displacement, but opposite in sign, and the acceleration and displacement are related by the square of the frequency. Harmonic motion is motion that is repeated over and over again. Angular velocity to frequency f = ω / 2 π frequency of number of full rotations / second Choose an origin or zero point In finding center of mass make sure the first thing you do is? Newton's first law of motion a body at rest or in motion with constant velocity will remain that way unless a force acts on it What is the definition of stress and strain of solids? Both fluids and solids resist compression with similar strength, although solids are generally less compressible. Solids are much more resistant to stretching than liquids. The idea of pressure remains useful in studying solids. It is renamed "stress" and (unlike pressure for fluids) its sign is now taken to be negative if the stress tends to reduce the volume of a sample. It still has units of Newtons per square meter, or Pascals. We can also talk of the compression force per unit area, i.e. the pressure. P = F/A. Sometimes stress is given the code σ . Strain is the extent to which a body is distorted when a deforming force (stress) is applied to it. It is a ratio of the strain is the ratio of the change in length of a body to its original length: ε = strain = ΔL/L0. ε denotes strain. Elastically – When an applied stress is removed, the material returns to its undeformed state. Linearly elastic materials, those that deform proportionally to the applied load, can be described by the linear elasticity equations such as Hooke's law (F=kx). When the piston expands is work being done on or done by the system? work is being done by the system what is i positive and i negative i positive is real image, i negative is virtual image What are the energies of a spring? The total mechanical energy of a mass m, on a spring, when no other forces do work, is given by the sum of the kinetic and potential energies. E = 1/2 mv^2 + 1/2 kx^2. Potential energy = PE = ½kx^2. Kinetic energy = KE = ½mv^2. At the equilibrium position x = 0, PE = 0, KE = maximum. At the maximum displacement (amplitude) x = A, PE = maximum, KE = 0. It is easy to evaluate E in terms of the amplitude A of the motion, because v = 0 when x is at its maximum value of A and E = 1/2 kA^2 because there is no KE. At any point, PE + KE = maximum PE = maximum KE = constant. Maximum PE = 1/2kA^2 = maximum KE = 1/2m(vmax)^2. If you are given the velocity at the equilibrium position, then you should be able to find out the amplitude by setting maximum KE = maximum PE. If you are given the amplitude, then you should be able to find out the velocity at the equilibrium position by setting maximum PE = maximum KE. The speed increases by the inverse of that amount at the point that has the smaller area In a flow rate situation, what happens if the area of a certain point is decreased compared to a previous point? How can a force have no torque? If the line of action of force passes thru the pivot point, then the force will no torque What is acceleration and what are the key kinematic formulas to memorize? Acceleration is rate of the change of the velocity vector with time. Average acceleration is change of velocity over change of time and it is uniformly accelerated motion along a straight line. In solving acceleration equations, we would be solving for average acceleration, because the only other type of acceleration is instantaneous acceleration, and you need calculus for that. You need to assign one direction as + and the opposite as -, and then keep this scheme for all your calculations. For Cartesian coordinates, take upward and rightward motion as positive; down and left as negative. For free falls, take downward as positive. When working with acceleration problems, pay attention if the acceleration is uniform (constant). Constant acceleration means that you can solve for average velocity. Otherwise, you cannot use the average velocity equation (x = 1/2(vf + vi)t). What are the two different types of units? 1. Derived -- those made in terms of other units. 2. Standard -- those which are compared to a standard. How strong is the electric field btwn the plates of a capacitor? How much energy is stored? E = V/d, where d is the distance btwn plates (note: E is uniform). PE =½ CV². A dielectric increases capacitance. W= p= mv F= G(m1m2/r^2) Fc= mv^2/r longitudinal wave Luminosity Candela (c) two common triangles Resistance Ohm = V/A Kilo k = 10^3 Nano n = 10^(-9) Current Ampere (A) = C/s Frequency and period f = 1/T Pascal's principle (hydraulics) F/A = F/A sin 180, cos 180 0, -1 Newton's first law law of inertia shear modulus modulus for shear stress Gravity Ubiquitous attractive force existing between any two objects, whose magnitude is directly proportional to the product of the two masses observed and inversely proportional to the square of their distance from each other. (F = G([m₁*m₂]/r²]) where G is the gravitational constant. Displacement Vector quantity describing the straight-line distance between an initial and a final position of some particle or object. Coulomb's law F = kqq / r² work transfer of energy using force; measured in joules Dielectric Constant Dimensionless number that indicates the factor by which capacitance is increased when a dielectric is placed in between the plates of a capacitor, given by C' = KC, where C' is the new capacitance. Pressure Force per unit area : F/A Bernoulli's Equation Equation describing the conservation of energy in fluid flow, given by P₁ + (1/2)ρV₁² + ρgy₁ + P₂ + (1/2)ρv₂² + ρgy₂. Magnetic field within wire loop B2r = μ₀I Diffusion/effusion r₁ / r₂ = √(MM₂ / MM₁) period (T) the reciprocal of frequency; the number of seconds required for one wavelength to pass a fixed point density of water 1000 kg/m^3 aka 1 gm/cm^3 mechanical energy kinetic and potential energy of macroscopic systems electromagnetic wave traveling oscillation of an electric and a magnetic field; ex: light inelastic collisions lose some energy to internal energy three types of waves 1. mechanical 2. electromagnetic 3. matter uniformly accelerated motion motion with constant acceleration; both direction and magnitude of the acceleration must remain the same Thermodynamics Study of heat transfer and its effects. Intensity Power transmitted per unit area, given by P = IA. I = Intensity, A = Area, P = Power. Diffraction Spreading-out effect of light when it passes through a small slit opening. Electric Field Electrostatic force that a source charge qs would exert on a positive test charge q₀ within its proximity divided by that test charge; E = F(coul)/q₀ Speed of Light Speed of electromagnetic waves traveling through a vacuum, given by the equation c = λf = constant equal to 3.00 x 10⁸m/s Normal Force Perpendicular component of the force caused when two surfaces push against each other, denoted by Fn. Electron Volt Voltage created by a potential difference between the two terminals of a cell when no current is flowing. Conduction Form of heat transfer where heat energy is directly transferred between molecules through molecular collisions or direct contact. Amplitude Point of maximum displacement from the equilibrium position. Frequency Number of cycles per second measured in SI units of Hz, where 1 Hz = 1 cycle/second RMS Voltage V(max)/(√2); average voltage in an AC circuit, where voltage alternates in a sinusoidal pattern. Fission Nuclear reaction in which a large nucleus splits up into smaller nuclei. Fluorescence Phenomenon observed when an atom is excited by UV light and the electrons return to the ground state in two or more steps, emitting photons of lower frequency (often in the visible light spectrum) at each step. Electromagnetic Spectrum Full range of frequencies and wavelengths for electromagnetic waves broken down into the following region, in order of descending/decreasing λ: radio, infrared, visible light, ultraviolet, X-ray, Gamma Ray. Doppler equation f' = f(1 ± v / c) beta decay expulsion of an electron (type of radioactive decay) critical angle the angle of incidence above which total internal reflection occurs; angle at which light is reflected stress force applied to an object divided by the area over which the force is applied simple harmonic motion motion that creates a sinusoidal function in time harmonic series the list of wavelengths from largest to smallest of the possible standing waves for a given situation; numbered from longest to shortest wavelength electric dipole created by two opposite charges with equal magnitude nonconservative force change in mechanical energy when work is done; ex: kinetic frictional forces and the pushing and pulling forces applied by animals Mass Scalar quantity used as a measure of an object's inertia. Continuity Equation Equation following the law that the mass flow rate of fluid must remain constant from one cross-section of a tube to another, given by A₁V₁ = A₂V₂ Half-Life Amount of time it takes for one-half of a radioactive sample to decay, given by the equation T1/2 = ln2/λ. λ = decay constant. Binding Energy Energy that holds the protons and neutrons together in the nucleus, defined by the equation E = mc². m = mass defect, c = speed of light in a vacuum. Focal Length Distance between the focal point and the mirror or lens. For spherical mirrors, focal length is equal to one-half the radius of curvature. Electric Circuit A conducting pathway that contains one or more voltage sources that drive an electric current along that pathway and through connected passive circuit elements, such as resistors. Capacitance Farad (F) = A*s/V = J/Ohm = C/V Linear motion position and time x = v₀t + (1/2)at² fusion the combing of two nuclei to form a single heavier nucleus equipotential surfaces points in an electric field that have the same voltage fluid pressure pressure at some point within a fluid; results from the impulse of molecular collisions Transverse Wave Type of wave, such as light, whose oscillation is perpendicular to its direction of motion. Wave Speed Speed of a wave, related to the frequency and wavelength. v = fλ Plane-Polarized Light Light that has been passed through a polarizing filter, allowing only the transmission of waves containing electric field vectors parallel to the lines of the filter. Absolute Pressure Pressure below the surface of a liquid that depends on gravity and surface pressure, calculated by P = P₀ + ρgz. P = Absolute pressure. z is depth. P₀ is the surface pressure. ρ = is the density. Loop-Wire Magnetic Field Magnetic field produced at the center of a circular loop of current-carrying wire, with a radius of r, calculated by: B = µ₀i/2r random translational motion motion of a fluid that contributes to fluid pressure (as in a fluid at rest) rms value found by taking the square of all the terms, then taking the average, and then taking the square root Potential Energy Energy of an object due to its height of ground level. PE = mgh Real Image An image produced at a point where the light rays actually converge or pass through. For mirrors, this would be on the side of the object, for lenses, it would be on the opposite side of the object. uniform translational motion motion of a fluid as a whole; doesn't contribute to fluid pressure Power Dissipated by Resistor Rate at which the energy of flowing charges through a resistor is dissipated given by the equation P = IV Permeability of Free Space, µ₀ Term denoted by µ₀ and equal to 4∏ X 10⁻⁷. Tesla meter/ampere; used in the equation measuring the magnetic field produced by a current-carrying wire, B = µ₀I/2∏r.
/ 222
Term:
Definition:
Definition:

#### Comments ({[ getComments().length ]})

{[comment.username]}

{[ comment.comment ]}

View All {[ getComments().length ]} Comments
Ask a homework question - tutors are online