MCAT-Physics
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Complete list of Terms and Definitions for MCAT-Physics

Terms Definitions
Q =Av
massXgravity weight=
Centi? 10^-2
Pressure (P=) F/A
Focal length f=R/2
speed and direction Velocity=
What is circumference?
λ= (for open pipes) 2L/n
inelastic collision KE not conserved
What is instantaneous velocity? Picture.
inelastic collision where mechanical energy changes but momentum is still conserved
Angular Frequency ω. equal to √(k/m)
vo/g In conservative total mechanical energy questions, the formula for time is?
SI unit for Mass Kilogram (kg)
thin lens equation f=(p*q)/(p+q), 1/f=1/p+1/q, f=focal length p=object distance q=image distance
Are real images upright or inverted? Inverted
Kelvin Most commonly used temperature scale (SI units), ranges up from absolute zero. Tk = Tc +273
Nm (Newton meter) The unit of Torque?
Insulator Electric charges cannot move easily (rubber, wood, glass, ...)
destructive interference waves interact out of phase
Focal length of a spherical mirror F=R/2
qE Force on q in an electric field=
Wavelength Quantity Equal to the distance between any two equivalent consecutive points along a wave, such as two consecutive crest peaks, expressed as λ.
Viscosity Measure of internal friction in a fluid, often denoted by µ
A ________ is a physical quantity characterized by both magnitude and direction. Vector
Static friction No relative motion between the surfaces that are in contact is what type of friction?
Is kinetic energy conserved in a completely elastic collision? Yes.
Audible range for humans 20 to 20,000 Hz
What is the relationship between the object distance and object size and the image distance and image size in concave mirrors?
Tension • a force acting through a flexible object with no mass, such as a string or rope. • tension is equal throughout the rope as long as there is no friction acting n the rope • trick: but, the rope has no mass ∴ if a net force were applied to only 1 end of a rope it would accelerate at an infinite rate
Work of a force perpendicular to the displacment W=0
Nonconservative Force A force, like friction, that performs work over a distance that is dependent on the path taken between the initial and final positions.
When acc is constant When to use big 5
specific gravity specific gravity = ρ substance/ ρ H₂O No units
What kind of frequency have greater indices of reflection? high frequency
spring constant (k) larger k means stronger, stiffer spring
What is lens aberration? ■spherical aberrations: not all light will focus at the focal point. For lenses made with spherical surfaces, rays which are parallel to the optic axis but at different distances from the optic axis fail to converge to the same point in the case of spherical abberation. Chromatic abberation: blue light gets refracted more than red light, so different colors focus differently. Blue light refracts more than red light because of Snell's law and because blue light has a higher refractive index. A lens will not focus different colors in exactly the same place because the focal length depends on refraction and the index of refraction for blue light (short wavelengths) is larger than that of red light (long wavelengths). The amount of chromatic aberration depends on the dispersion of the glass. A lens will not focus different colors in exactly the same place because the focal length depends on refraction and the index of refraction for blue light (short wavelengths) is larger than that of red light (long wavelengths). The amount of chromatic aberration depends on how the glass disperses light. Chromatic dispersion is the change of index of refraction with wavelength. Generally the index decreases as wavelength increases, blue light traveling more slowly in the material than red light. Dispersion is the phenomenon which gives you the separation of colors in a prism. It also gives the generally undesirable chromatic aberration in lenses.
√(2gD) (square root), D is distance from liquid surface down to the hole v of efflux=
Transverse Wave Type of wave, such as light, whose oscillation is perpendicular to its direction of motion.
In the simplest, ideal case (no friction and nothing attached to the block), the only forces acting on a block on an inclined plane are gravity p ushing straight downward, and the inclined plane pushing back. The force of the inclined plane pushing back a normal force (F_n)
Exert a torque To make an object spin we must?
radius of curvature r= distance from center of curvature to mirror or lens
phase difference crests of two waves don't occur at same point in space
How do you resolve a vector to Cartesian x-coordinates? This formula
What is Continuity equation? One of the fundamental principles used in the analysis of uniform flow is known as the Continuity of Flow. If steady flow exists in a channel, there exists a continuity of flow, defined as: &quot;The mean velocities at all cross sections having equal areas are then equal, and if the areas are not equal, the velocities are inversely proportional to the areas of the respective cross sections.&quot; Thus if the flow is constant in a reach of channel the product of the area and velocity will be the same for any two cross sections within that reach. Looking a the units of the product of area (square-feet) and velocity (feet per second) leads to the definition of flow rate (cubic feet per second). This is expressed in the Continuity Equation: Q = a1v1 = a2v2. Where: Q = the volumetric flow rate (also called volume flux and it's change in volume over time) and it is constant throughout the channel. A = the cross sectional area of flow and V = the mean velocity. Q is expressed as cubic feet per second or cubic meters per second. This is the flow of an IDEAL fluid. Where the channel is the narrowest, the flow speed is greatest. The short hand way is if a problem gives the diameter of a circular part of a channel, just square the diameter to get the area if it's comparing to the channel with a different circular part because π just cancels out. I just need to make sure to use AREAS when using this equation. Always remember that in ideal fluids, volumetric flow rate remains constant at all times. The flow rate is volume of fluid passing any point in a given second. With volume flow rate, the volume of fluid flowing in must equal the volume of fluid flowing out. However, when dealing with containers that spills out water, this rule does not quite work because you're dealing with gravity. The velocity of the fluid is based on the height and on gravity. So the flow rate changes. The flow rate being constant is for a channel. With ideal fluid, fluid does NOT always move from high pressure to low pressure, it depends on other factors like gravitational forces. A fluid flows in the direction that will dissipate its energy between gravity, velocity, and pressure.
What is Continuity equation? Since ideal fluids are incompressible, their volume remains constant. The volume of a fluid moving through a section of pipe is given by the cross-sectional area (A) of the pipe times the distance (d) of the pipe section. If this same volume of fluid moves completely through this pipe section in a given time (t), the rate (Q) at which volume passes through the pipe is Ad/t. Since the fluid moves a distance d in time t, its velocity is v = d/t. Therefore, Q = Av. Flow can be given in terms of mass as well. For the mass flow rate (I) multiply the volume flow rate by density I = ρQ = ρAv or mv. This is momentum (mass time velocity). In an ideal fluid, flow rate is constant. Area is inversely proportional to velocity; the narrower the pipe, the greater the velocity. Pressure has no direction. The driving force behind the direction of fluid flow is the fluid's tendency to find its greatest entropy. If all other things are equal, fluid will move from high pressure to low pressure. In a horizontal pipe of constant cross-sectional area, fluid will flow from high pressure to low pressure according to: ΔP = QR, where R is the resistance to flow and Q is the flow rate.
Does a decrease in KE (aka temp) of a real gas necessarily mean an increase in PE (IMFs)? Yep
is the force opposing motion when two contiguous surfaces are not moving relative to each other. Static friction (f_s)
Newton's Law of Gravitation Every pair of object exerts a gravitational attraction on each other, with strength F= GMm/r²
How are frequency of period and waves related? reciprocals   v =  fλ   k=2∏/λ
What are harmonics? •The fundamental frequency is called the first harmonic (n = 1). The next-up frequency is called the second harmonic (1st overtone) (n = 2). Harmonics are not overtones, when it comes to counting. Even numbered harmonics are odd numbered overtones and vice versa. A harmonic of a wave is a component frequency of the signal that is an integer multiple of the fundamental frequency. For example, if the fundamental frequency is f, the harmonics have frequencies f, 2f, 3f, 4f, . . . etc. The harmonics have the property that they are all periodic at the fundamental frequency, therefore the sum of harmonics is also periodic at that frequency. Harmonic frequencies are equally spaced by the width of the fundamental frequency and can be found by repeatedly adding that frequency. For example, if the fundamental frequency is 25 Hz, the frequencies of the harmonics are: 25 Hz, 50 Hz, 75 Hz, 100 Hz, etc. Music has harmonic frequencies of 2, so if you start with a fundamental of 2 Hz, then the second harmonic is 4Hz, the third harmonic is 6Hz, etc.
What are harmonics? A list of the wavelengths from largest to smallest of the possible standing waves for a given situation is called a harmonic series. The harmonics is numbered from longest to shortest wavelength.
Centripetal Force (Fc) Fc = mv² / r • acceleration must be accompanied by a net force • centripetal force must be either: - Gravity - EM - Contact ex: Gravity creates the Fc that makes a satellite orbit the earth rather than fly away. Its velocity makes it continually miss the ground and always by the same distance ∴ appears to be floating away
Power Dissipated by Resistor Rate at which the energy of flowing charges through a resistor is dissipated given by the equation P = IV
flow rate flow rate, f, is the amt of (vol) of fluid that flows per unit time so [f] = m³/s. By contrast [flow speed] = m/s
Describe potential and kinetic energy during simple harmonic motion U=0 and K=max at equilibrium point   U=max and K=0 at maximum displacment
What is the law of gravitation? Newton's law of universal gravitation states that every massive particle in the universe attracts every other massive particle with a force which is directly proportional to the product of their masses and inversely proportional to the square of the distance between them. Gravity decreases with the square of the distance. If the distance increases two fold, gravity decreases by a factor of four. The &quot;distance&quot; is the distance from the center of mass between the two objects, not the distance between the surfaces. Gravity is the weakest of the four universal forces. This weakness is reflected in the universal gravitational constant, G, which is orders of magnitude smaller than the Coulomb's constant. The gravitational force EVERYWHERE inside a uniformly dense sphere or ring, due THAT sphere or ring (not another) is zero because there is no radius that we're calculating from. So, if you have an object anywhere inside that sphere or ring, it won't feel a gravitational force due to that ring. However, if there is another sphere or ring that is exerting a gravitational force separate from the sphere or ring the particle is on, then it will experience a force from that ring. For objects bound in orbit, the total energy has to be negative because the potential energy has to be greater than the kinetic energy and the potential energy is negative. Otherwise, the objects would escape the orbit and overcome the potential energy with it's kinetic energy and would leave the orbit. The gravitational force would not be able to perform enough work to slow the object down as it went out the orbit. The units for electric field is N/C while the units for gravitational field is N/kg.
Is high frequency or low frequency light refracted more? High frequency (aka blue light refracts more than red light)
resistance R = V/I ; [R] = ohms (Ω) , where 1Ω = 1V/A
What kind of charges attract and repel? like charges repel, unlike charges attract
What is Archimedes’ principle (buoyancy)? Buoyancy: is an upward acting force, caused by fluid pressure, that keeps things afloat. ◦Archimedes' principle: buoyant force on an object = weight of the fluid displaced by the object. FB is bouyant force. ◦FB = weightdisplaced = mdisplaced*g =ρfluid*Vdisplacedfluid*g. Things float when FB &gt; Weight. The fluid displaced has a weight W = mg. The mass can now be expressed in terms of the density and its volume, m = pV. Hence, W = pVg.It is important to note that the buoyant force does not depend on the weight or shape of the submerged object, only on the weight of the displaced fluid. Archimede's principle applies to object of all densities. If the density of the object is greater than that of the fluid, the object will sink. If the density of the object is equal to that of the fluid, the object will neither sink or float. If the density of the object is less than that of the fluid, the object will float. If an object is submerged it displaces a volume of fluid equal to its own volume. If it is partially submerged it displaces the volume of fluid equal to its submerged volume. If an object is submerged, the volume that the object is submerged is equal to the displaced volume. If the object is floating (not submerged), the weight of the object is the buoyant force (you don't need the volume).
What is Archimedes’ principle (buoyancy)? Put in other words, the buoyant force is the weight of the object minus the weight of the fluid. A floating object displaces an amount of fluid equal to its own weight. The floating equation says that the SUBMERGED FRACTION of a floating object is equal to the ratio of the density of the object to the density of the fluid in which it is floating. If the object is floating in water, this ratio is the specific gravity of the floating object. Since buoyant force is equal to the &quot;difference&quot; in pressure, the buoyant force does not change with depth. Another way to understand buoyant force is as a result of the pressure difference between the upper and lower surfaces of a submerged object. Since pressure increases with depth, the lower surface of an object experiences greater pressure than the upper surface. This pressure difference multiplied by the upper or lower surface area is equal to the buoyant force because FB = pVg and V = AΔh, so FB = pgAΔh. FB/A = pgΔh and ΔP = pgΔh. A fully submerged object displaces its VOLUME in fluid, a floating object displaces its WEIGHT in fluid.
Is "f" positive or negative in Convex mirrors? Negative (rays converge on opposite side of source)
Calc g ? g = GM/r² , where M = mass of planet, r = distance from given location to center of planet
What are lens strength and diopters for thin lens? ■Lens strength, or lens power is measured in diopters. ■P = 1/f f is the focal length and it is in METERS. ■where P is in diopters. The most important characteristic of a lens is its principal focal length, or its inverse which is called the lens strength or lens &quot;power&quot;. Optometrists usually prescribe corrective lenses in terms of the lens power in diopters. The lens power is the inverse of the focal length in meters: the physical unit for lens power is 1/meter which is called diopter. This power is not the same as the power in mechanics. If the focal length is negative, then the power will be negative and it's a diverging lens or mirror.
What determines the frequency of a spring-block simple harmonic oscillator? Mass of block and force constant of spring: f=(½π)√(k/m)
Addition in a series Rs = R1 + R2 .... Rn   1/Cs = 1/C1 + 1/C2 .... 1/Cn
What are the analysis of pulley systems? Pulleys reduce the force you need to lift an object. The catch - it increases the required pulling distance. •Rule of thumb: The ropes on either side of a moving pulley contributes to pulling the load. •The MCAT will most probably give you simple pulleys where only the above rule is applicable. •Complex pulleys will have additional ropes that contribute to the pulling of the load (most likely not tested on the MCAT). •The distance of pulling increases by the same factor that the effort decreases. Pulleys (anything of mechanical advantage) reduce the amount of force required, but does not affect work. Pulleys (and ramps and levers) allow force to work over a greater distance and do the same amount of work with less force. They key to understanding pulleys is remembering that tension throughout a massless, frictionless pulley is constant. If you have 1 rope, the tension is the same at every point of the rope and the force necessary to lift the mass is mg (the weight). The best way to solve pulley problems is to first figure out the tension of the rope holding the mass, then equate that tension to the force required to lift the mass. Tension in a single rope in an ideal pully is the same throughout the rope. So if you calculate the tension of 1 part of a rope in a pulley, then all ropes have that tension, and that tension is equal to the minimum force needed to pull the pulley and lift the mass.
No it is just the name given to a force that acts this way so it can be anything There is an actual centripedal force?
What is absolute potential at point in space? ■Absolute potential (V) is the amount of energy per charge that something possesses. V = U/q0 = k(q/r). For a point charge the absolute potential (or electric potential) of any position in its electric field is U = k(q/r). It is the electric potential energy (U) divided by charge associated with an electric field (q0). V is the electric potential (absolute potential) caused by q, which is experienced by q0. q is the charge that is causing the potential, not the charge that's experiencing the potential and it is the point charge. Traditionally, q0 is the charge experiencing the potential and it is the test charge. The magnitude of q0 is very small. U is the electrical potential energy possessed by q0. ■r is the distance between the potential-causing charge and the charge that's experiencing the potential (r is always positive). If there are multiple charges contributing to the potential, then calculate the potentials each of them causes (positive charges cause positive potentials, and negative charges cause negative potentials), and sum them together. The unit for electric potential is Volts (V) or Joules per Coulomb (J/C).
What is absolute potential at point in space? Make sure to know the difference in problems with whether you are working with point charges or with a constant electric field like with capacitors. Use the q1 and q2 equations if you're working with point charges, and use the equations that don't have q1 and q2 if you're working with a constant electric field (a field with no point charges).
Since gravity and the normal force are the only forces acting on the block resting on an inclined plane, their sum is called the net force. It is the net force that should be plugged into Newton's second law to find the acceleration of your system.
How do you solve a projectile question about long it spent in the time in the air or how far it travelled? What is the time the projectile is in the air? Ans: use the vertical component only- calculate the time it takes for the projectile to reach the maximum height - this is when the vertical velocity is zero because this is terminal velocity. Then multiply this time by 2 because this is only half the flight time - the flight time up is equal to the flight time down. •How far did the projectile travel? Ans: first get the time in the air by the vertical component. This time in the air is double the time found by the vertical velocity. Then multiply the horizontal component's speed by the time of flight. The horizontal component's speed does not change throughout the flight, so that is why we can multiply the time of flight by the horizontal speed to get the range. Understand that vertical velocity dictates time of flight. If 2 projectiles leave the earth with the same vertical velocity, they will land at the same time, regardless of their horizontal velocities. More massive objects fall faster (have greater velocity) than less massive objects due to air resistance because they are acted upon by a larger force of gravity; for this reason, they accelerate to higher speeds until the air resistance force equals the gravity force.
How do you solve a projectile question about long it spent in the time in the air or how far it travelled? For a projectile without air resistance, the range is maximized at 45°. Subtracting or adding to the angle of trajectory from 45° by equal amounts results in equal ranges. For instance, 30° and 60° are both 15° from 45° and result in the same range. The velocity of a projectile experiencing no air resistance is independent of mass. Height is maximized at 90°. Only VELOCITY changes at a constant rate with projectiles, not SPEED. As the projectile climbs, the speed of it decreases, as the projectile falls, the speed increases. For circular motion, speed is constant, but the velocity is constantly changing.