MCAT Physics 10 Flashcards

Terms Definitions
(displacement) ∆x=?
charging a capacitor
∆L(angular momentum)/∆t
Torque (τ)=
Shear Modulus
shear stress modulus
Gravitational force, note: G=0.666*10^-10 Nm^2/Kg^2
Power (P)
Work (W)
Time (t)
What are convex mirrors?
Patm or surface + Pgauge
units for accelleration
m/s/s or m/s^2
Potential Energy
ΔPE = qΔΦ =qV
average velocity
displacement vector over time
Point of rotation
• the position vector
Quantity with both magnitude and direction: velocity, acceleration, force, momentum, etc.
E is always represented in Joules
Objects stick together afterwards
Perfectly inelastic collision
what is the magnification
m = -i/o
electrostatic force
force between two stationary charges
4 forces in nature
1. Strong
2. Weak
3. Electric/electromagnetic
4. Gravity
emphasis on 3 & 4
the direct transfer of energy via molecular collisions
Study of heat transfer and its effects.
Alpha Decay
Nuclear reaction in which an α-particle (⁴₂He) is emitted.
________ fall is motion with no acceleration other than that provided by gravity.
W/t = Fd/t = Fv
Power also equals
period, T
time required for oscillator to complete one full cycle
average speed
scalar quantity of distance traveled over time
Longitudinal wave
vibrationjs parallel to direction of propogation-sound waves
How do you create a dihybrid cross?
Constant of porportionality for Tensile strain
Young's modulus is (E)?
Diamagnetic Material
Material whose atoms have no net magnetic field. The material is therefore repelled from the pole of a magnet.
________ is anything that can cause a massive body to accelerate. It may be experienced as a lift, a push, or a pull.
The watt, joules/seconds
Power is measured in what units?
an optical device (thin piece of glass or plastic) that forms images by refracting light
(T/F) For a planet orbiting a star, the centripetal force is equal to the gravitational force.
Critical angle
limiting angle of incidence in the optically denser medium that results in an angle of refraction of ˚90
What are inelastic collisions?
◦Conservation of momentum only. ◦Kinetic energy is lost during an inelastic collision due to heat or other non-conservative force. ◦Collisions in everyday life are inelastic to varying extents. ◦When things stick together after a collision, it is said to be a Perfectly inelastic collision. But many inelastic collisions just involve objects who have the same equal and opposite or the same velocities (from momentum), but lower speeds (from kinetic energy). The equation for inelastic collisions is: m1v1 + m2v2 = (m1+m2)*vfinal. The final velocity of the stuck together masses (m1 and m2) is vfinal. v1 and v2 are the initial velocities of the masses. With ELASTIC collisions, note this question: With one mass AT REST, as the mass of the incoming mass increases, how do the final velocities of each mass relate to the initial velocity of the incoming mass? Answer : As the incoming mass gets bigger .. it's velocity stays the same as the initial velocity that it had, and the other mass's velocity will start to approach twice the initial velocity of the incoming mass! Also, say you have an object m2 with a mass three times greater than m1, and m2 is at rest and m1 strikes m2, what is the velocity of m2 in an elastic collision? Well, first know that m1 has a smaller mass than m2, so it will bounce in the opposite direction. Because of this, it's final momentum is going to be negative. The m2 will have a positive momentum. So when figuring out the velocity of m2, know that whatever the velocity is, it has to create a momentum that is greater than the initial momentum of m1, because the final momentum of m2 and final momentum of m1 (which is negative) have to equal the initial momentum of m1. Once again, it's not the individual momentums that are conserved (and KE for elastic collisions), but the sum of the momentums and KEs.
What are inelastic collisions?
For inelastic collisions, initial momentum is equal to final momentum.
The initial momentum of an isolated system equals the final momenturn of an isolated system. However, because momentum is a vector, we must pay close attention to its direction. In a 2 dimensional system, if we have momentum in both the x and y
directions, one equation is required for each direction.
How do you find higher fundamental frequencies?
f(n) = n*f(1)
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.
Resistance SI symbol and units
Ohm (omega) 1 omega=1 V/A
Lever arm
distance from pivot point to the line of action of force
τ = lF
Describe force on a current carrying wire in a magnetic field.
F = iLBsinθ
What is static friction?
Static friction is friction between two solid objects that are not moving relative to each other. An object can sit still on an inclined plane because of static friction. •Static friction is always larger than kinetic friction. •The coefficient static friction is always larger than the coefficient of kinetic friction. The force of friction is always exerted in a direction that opposes movement (for kinetic friction) or potential movement (for static friction) between the two surfaces. If you have 3 objects with the same shape and material and masses 1kg, 2kg, and 3kg, on a board and the board is lifted on one end, all objects will slide at the same time (it's not dependent on the size of the object). Why? Because the maximum static frictional force occurs just before the block begins to move. At that moment, the block is in static equilibrium, so the net force is zero. That means the force up the plane equals the force down the plane. The force down the plane is mgsinθ. The force up the plane is static friction. Thus μmgcosθ = mgsinθ. So μ = sinθ/cosθ. θ is the angle at which any block will slide, it is independent of mass. Force is dependent on mass, inertia is dependent on mass. The angle of an incline, acceleration, distance the block travels, time the block takes, and speed that the block slides are not. Kinematic equations use acceleration, which is independent of mass. Pay attention to where the mass on an incline wants to move to or is moving to...if it's moving up an incline, then the force of friction is down the incline. If it's moving down the incline or wants to move down the incline (if it's being held stationary), then the force of friction is up the incline. The net force is the direction of force of friction (which could be up or down, opposite the motion) and the gravity component of the object (which is down), and any extra force applied (which could be up or down). Static friction has to be overcome to start an object moving. To determine if a block will move or not, set up an relationship to compare the parallel component of the weight of the block to the parallel component of static friction. So if Fmg > Fs, the block will slide. This is mgsinθ > μmgcosθ. If any value of μ is greater than the μ in this equation, the block will not move. If μ is smaller than this equation, then the block will move.
What does electromagnetic radiation consist of?
■radiation consists of oscillating electric and magnetic fields that are mutually perpendicular to each other and to the propagation direction. Light, electricity, and magnetism are manifestations of the same thing called electromagnetic radiation. The electric and magnetic fields oscillate at right angles to each other and the combined wave moves in a direction perpendicular to both of the electric and magnetic field oscillations. This energy also comes in many forms that are not detectable with our eyes such as infrared (IR), radio, X-rays, ultraviolet (UV), and gamma rays.
Conservation of Mechanical Energy
When only conservative forces act on an object and work is done, energy is conserved and described by the equation: ΔE = ΔKE + ΔPE = 0
↖ because v2-v1 is v2 + (-v1) so it really is ← +↑
A one-eyed person standing in hip deep water sees a fish in the water one meter in front of him. the fish appear to be
larger and farther
What are alternating currents?
In alternating current (AC, also ac) the movement (or flow) of electric charge periodically reverses direction. An electric charge would for instance move forward, then backward, then forward, then backward, over and over again. In direct current (DC), the movement (or flow) of electric charge is only in one direction. The usual waveform of an AC power circuit is a sine wave. Alternating current is in simple harmonic motion. Maximum current occurs when electrons are at their maximum velocity. The maximum voltage is sqrt(2) * root-mean-square velocity and maximum current is sqrt(2) * root-mean-square current.
What is Surface tension?
◦Surface tension gives the surface of a liquid the ability to support things that are very light.
◦For example, insects can walk on water due to surface tension.
◦Surface tension is due the attraction between the molecules of the solvent.
Surface tension is the intensity of the intermolecular forces per unit length. Much like a spring, when the molecules at the surface of the water are pushed downward by the weight of the needle, the intermolecular bonds of the water are stretched, and push upward with a force. Surface tension is also responsible for the formation of water droplets. Intermolecular forces pull inward tending to minimize the surface area by creating a more spherical shape. A sphere has the least surface area per volume of any shape. Since surface tension is a function of the intermolecular forces, it is dependent upon the temperature of the fluid (the higher the temperature, the weaker the intermolecular forces because the molecules have more energy and move about more and can escape, and so the weaker the surface tension) and upon the fluid with which it is interfacing.
What is Surface tension?
Related to surface tension is the phenomenon of capillary action, where a fluid may be pulled up a thin tube. For capillary action, recognize that there are 2 types of forces acting: the intermolecular forces responsible for surface tension (cohesive forces); and the forces between the molecules of the tube and the fluid molecules (adhesive forces). If the cohesive forces are stronger, a convex meniscus is formed and the fluid is pulled downward by the vertical component of the surface tension. If the adhesive forces are stronger, a concave meniscus is formed and the fluid is pulled upward by the vertical component of the surface tension.
Yes, so they will spontaneously accelerate when moving toward lower potential
Positive charges naturally move to points of lower potential?
Finding one-dimensional motion (just falling)
Use the problem S=1/2 at2 (S=distance of falling, a=gravity constant)
Angle of incidence and the angle of reflection
has the same angle
What is beta decay?
Beta decay (beta decay) can be either electron emission or positron emission. In electron emission, the neutron to proton ratio is too great and a neutron is turned into a proton and an electron. The electron is then emitted. There is also positron emission when the neutron to proton ratio is too small. A proton turns into a neutron and a positron and the positron is emitted. A positron is basically a positively charged electron. With electron emission, the proton number increases by 1 because a neutron is converted to a proton, while with position emission, the proton decreases by 1 because the proton is converted to a neutron. Electron capture is one process that unstable atoms can use to become more stable. During electron capture, an electron in an atom's inner shell is drawn into the nucleus where it combines with a proton, forming a neutron and a neutrino. The neutrino is ejected from the atom's nucleus. Since an atom loses a proton during electron capture, it changes from one element to another. For example, after undergoing electron capture, an atom of carbon (with 6 protons) becomes an atom of boron (with 5 protons). So the atomic number decreases by 1, like with positron emission, but with electron emission, the atomic number increases by one. Although the numbers of protons and neutrons in an atom's nucleus change during electron capture, the total number of particles (protons + neutrons) remains the same.
What is beta decay?
Beta decay is the emission of an electron OR a positron. If the atomic number increases, then an electron is released. If the atomic number decreases, then the positron is released (positron emission). Beta particles are electrons or positrons.
What is amplitude and period?
◦Amplitude (A): how high the peaks are or how low the troughs are, in meters.
■The displacement is how far the wave vibrates / oscillates about its equilibrium (center) position.
■The amplitude is the maximum displacement.
■Amplitude is correlated with the total energy of the system in periodic motion. Larger amplitude = greater energy.
◦Period (T): the time it takes to complete one cycle. The unit of period is seconds. ■T = 1/f. The period is the duration of one cycle in a repeating event, so the period is the reciprocal of the frequency. Period = seconds/cycle
When looking at waveforms on a graph, the period may not seem as obvious if it's not a sinusoidal graph (y = Asin(wt)). However, just look to see when the waveform starts to repeat itself on a displacement (y) versus time (x) curve. When the waveform starts to repeat itself, that is when it has completed one full cycle and the time that it starts to repeat itself is the time it took to complete one cycle. The less defined wave forms are usually the result of interference from waveforms of a number of frequencies.
If you are given a problem that says that the range of amplitudes for two waves is between 4 and 12, that means that possible wave units could be 8 and 4 - maximum destructive interference could occur at 8-4 = 4 units and maximum constructive interference could occur at 8+4 = 12 units.
What is amplitude and period?
Frequency is related to both wavelength and period by inverse relationships. There is no direct mathematical relationship between amplitude and frequency.
Work done by all nonconservative forces
• equals the change in mechanical energy (∆KE + ∆PE) of the systems upon which they are applied
W = ∆KE + ∆PE
(nonconservative forces other than kinetic friction, no heat)
How to express radians and degrees
know 360*=2pie, so 2pie/360* X degree given =Randians
What is the simple harmonic equation
I = 1/2 p w2 A2 V
What is Supposition of waves, interference, and addition ?
◦When waves superimpose on each other, they interfere.
◦Interference results from the addition of waves.
◦When in phase waves add, the resulting wave has a greater amplitude.
◦When out of phase waves add, the resulting wave has a smaller amplitude.
◦Constructive interference: addition of waves resulting in greater amplitude.
◦Destructive interference: addition (cancellation) of waves resulting in diminished amplitude.
Two or more waves can occupy the same space. When this happens, if the waves are transverse, their displacements add at each point along the wave to form a new wave. This superposition of waves is called interference. After passing through each other, waves that interfere will revert to their original shape, unaffected
by the interference.
Any waveform, no matter how irregular, can be created by superposition of a sufficient number of sine waves with the correct amplitudes and wavelengths.
What is Supposition of waves, interference, and addition ?
The definition of interference is when the displacements (amplitudes) of two superimposed waves are summed along the wave.
Determine work done by a Kinetic Frictional Force
• must consider the Ei
ex: box sliding to a stop on a tabletop.
Kinetic Friction (Fk) has done (-) work on the box;
the force ⬇ the KE of the box
the mechanical energy (PE+KE) changes of the box
Fk • d • cosθ = ∆KE + ∆PE
the box ⬆ Ei, but since the box and table top are the same T there is no heat in this problem
----> all energy change is due to work ∴
W = ∆KE + ∆PE + ∆Ei ---> work done on the box
• the KE of the box became the Ei of the box and Ei of the table
forward force − (μF, friction) which gives you the net forward force
A lot of de/incline questions use what formula?
How is kinetic energy related to heat?
heat transferred into a system causes an increase in kinetic energy
How is Reynolds number related to turbulence with high velocities?
Turbulence does not begin to occur until the velocity of flow becomes high enough that the flow lamina break apart. Therefore, as blood flow velocity increases in a blood vessel or across a heart valve, there is not a gradual increase in turbulence. Instead, turbulence occurs when a critical Reynolds number (Re) is exceeded. Reynolds number is a way to predict under ideal conditions when turbulence will occur. Re increases as velocity increases and decreases as viscosity increases. Therefore, high velocities and low viscosity are more likely to cause turbulence. It makes sense that Re decreases as viscosity increases because think about it, how turbulent is honey? It's too thick to be turbulent. But water can be turbulent.
What are the charges of the electrodes in Electrolytic cells?
Anode is positive & Cathode is negative (makes sense because this isn't spontaneous)
When does an object float?
w object = B <=> ρ object ≥ ρ fluid
What is work and the Derived units, sign conventions?
Work is the amount of energy transferred by a force acting through a distance. Like energy, it is a scalar quantity. Work is greatest in size when the force is in the same direction as the distance that the object travels. Don't forget that F is the NET force on an object, so if there are multiple forces on an object, calculate the NET force and use that to find the work.
•W = Fdcosθ. •F is force, d is the distance over which the force is applied, and θ is the angle between the force and distance. This equation applies for all forces except friction. The force may be one of many forces acting on thc system or it may
be the net force. It is the energy transferred into a system due to a force. If the resultant force F on an object acts while the object is displaced a distance d, and the force and displacement act parallel to each other, the mechanical work done on the object is the product of F multiplied by d. ◦Work is energy, and the unit is the Joule. ◦Joule = N·m = kg·m/s^2·m = kg·m^2/s^2
Notice that W = Fdcosθ only works with cosθ when there is an angle between the force and the distance, if there is no angle between the force and distance (meaning the force acts in the same direction as the distance) than W = Fd. The force could be down the incline (with the object moving the same direction as the force of gravity, with no other applied forces), so the F = mgsinθ. This force would be multiplied by d to get work. Work done by an external force like friction is equal to the change in mechanical energy (because this energy that leaves is what makes frictional forces non-conservative - it's mechanical energy lost).
What is work and the Derived units, sign conventions?
There are only two types of energy transfer: work and heat. Work (W) is the transfer of energy via a force. Heat is the transfer of energy by natural flow from a warmer body to a colder body. Thus all work is energy transfer, but all energy transfer is not work (because it could be heat too). By 'transfer', we mean transfer from the system to the surroundings or vice versa. Therefore, the amount of work done will depend upon what we choose for our system. Frictional forces are an exception because frictional forces change internal energy as well as mechanical energy. (Internal energy is the energy of individual molecules). If the total energy transfer is due to forces and none to heat, the work done on an object is also given by: W = ΔK + ΔU + ΔEi. This is how frictional forces can change the internal energy. If there is neither heat nor friction: W = ΔK + ΔU, where internal energy is not changed. K is kinetic energy, U is potential energy and Ei is internal energy.
Equation for if the total energy transfer is neither heat nor friction, the work done on an object is:
W = ∆KE + ∆PE (no friction, no heat)
A box of mass, m, slides down a frictionless ramp with the incline angle ϑ. What is its acceleration?
a = (mg sinϑ)/m = g sinϑ
What is the third harmonic of a string?
The third harmonic of a guitar string is produced by adding two nodes between the ends of the guitar string. And of course, if two nodes are added to the pattern, then two antinodes must be added as well in order to maintain an alternating pattern of nodes and antinodes. In order to create a regular and repeating pattern for this harmonic, the two additional nodes must be evenly spaced between the ends of the guitar string. This places them at the one-third mark and the two-thirds mark along the string. These additional nodes give the third harmonic a total of four nodes and three antinodes. The standing wave pattern for the third harmonic is shown at the right. A careful investigation of the pattern reveals that there is more than one full wave within the length of the guitar string. In fact, there are three-halves of a wave within the length of the guitar string. For this reason, the length of the string is equal to three-halves the length of the wave. The diagram below depicts this length-wavelength relationship for the fundamental frequency of a guitar string.
what is the equation of the index of light?
n = c/v where c is the vacuum
The more difficult it will be to bend it or stretch/compress it respectively
The greater the number for G and E then?
/ 77

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