# MCAT Physics Formulas

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1. Calculating average speed
• d = distance
• t = time
2. Calculating average velocity
• displacement over time elapsed
3. Calculate average acceleration
• change in velocity over elapsed time
4. Relate change in velocity, acceleration, and time without position.
1-dimensional, constant acceleration
5. Relate change in position, initial velocity, acceleration, and time without final velocity. 1-dimensional, constant acceleration
6. Relate change in velocity, acceleration, and change in position without time. 1-dimensional, constant acceleration
7. Free fall from 0 velocity

• g = -9.8m/s^2
• h = height of fall
8. For a vector of magnitude v making an angle θ with the x-axis, what are the components in 2-dimensions?

at an angle
9. Centripetal acceleration toward the center of a circle with radius r for an object traveling with constant speed v
10. Newton's first law of motion (Equilibrium)

Every body continues in its state of rest or of uniform speed as long as no net force and no net torque act on it.
11. Newton's second law of motion (Dynamics)

acceleration of an object is directly proportional to the net force acting on it and is inversely proportional to its mass. Direction of a corresponds to direction of net F action on the object
12. Newton's third law of motion

Whenever one object exerts a force on a second object, the second exerts an equal and opposite force on the first.
13. Instantaneous velocity if position, x, as a function of time, t, is given as:

14. Relative motion in a moving frame, B.

• vA is object's velocity in a stationary frame
• VB is the velocity of the frame
15. Law of sines
16. Law of cosines
17. Projectile Motion: Horizontal Range and flight time if start and end height are equal.
•
• (max value) when
19. Projectile motion x and y travel components

t in x and y equations is the same, no acceleration in the x direction
20. Momentum
21. Centripetal force in uniform circular motion
22. Acceleration in nonuniform circular motion
• Separate acceleration vector into centripetal and tangential accelerations
•    and
23. Relate centripetal acceleration, orbital period, and radius
24. Hooke's Law of an ideal spring over a limited range of stretch/compression relates Force with distance of stretch given a constant, k.
25. Motion on an inclined plane (ignoring friction)
26. Static frictional force
27. Force of kinetic friction

28. Drag force moving through a fluid; relating density, area, and speed.

• C is the experimentally determined drag coefficient, ρ is the fluid density, A is the cross sectional area of the object, v is speed
• Direction opposite the object's motion relative to the fluid
29. Pulleys and opposing forces including friction (modified Atwood machine with opposing dangling masses A & C and mass B between them on a frictional surface)

No friction:
30. Universal Gravitation - the force of gravity between any 2 objects

m's are masses; r is the center-center distance
31. Universal Gravitation in a Circular Orbit

32. Torque (twisting force)

• F is force applied
• l is the length of the lever arm
33. Work (in Joules, J) done by a constant force of magnitude F on an object as it is displaced by a distance, d at an angle θ to each other.

34. Work from a varying force (1-dimension or 3-D)

35. Work from a spring (force varies with distance)
36. Fundamental Forces
• Gravitational - attractive force between all matter
• Electroweak (electromagnetic and weak nuclear) - virtually all of the nongravitational
• Color force (nuclear strong) - force between quarks, holds protons and neutrons together
37. Kinetic energy, K, for a mass, m, traveling at a speed, v.
38. Work-energy theorem: relating work due to nonconservative forces, W_nc and energy

The sum of the changes in kinetic, potential, and internal energy due to friction
39. Net Work and Kinetic energy
40. Conservative forces

• Gravitational, Elastic spring, & Electric forces
• Path Independent
41. Non-conservative Forces
• Friction
• Air Resistance
• Tension
• Normal Force
• Propulsion of a motor
• NOT path independent
42. Conservation of Mechanical Energy (ignores non-conservative forces)

43. Potential energy is the negative of the work done by a conservative force (general)
44. Potential energy with force and path parallel
45. Potential Energy with a constant force
46. Gravitational Potential Energy
• (close to Earth's surface)
• Generally:
47. Elastic (spring) potential energy

Set U=0 @ x=0:
48. Rest mass energy - the energy inherent to a particle by nature of it having a mass.
49. Power, P, is the rate at which work is done.  Also described in terms of force, F, and velocity, v and the angle, θ, between them.

in Joules/sec = Watts
50. Conservation of linear momentum

• Total momentum remains unchanged
51. Impulse

impulse = change in momentum = product of average force over a time interval
52. Elastic collisions: bodies do not stick together, internal forces conservative, no sound or heat
•   and
53. Totally Inelastic Collisions: bodies stick together, maximum loss of mechanical energy that supports conservation of momentum
54. Elastic collisions, special cases relating m1 and m2 and final velocities

• in 1-D if v2i=0
55. Center of Mass - average location for the total mass of the system
56. Density and Specific Gravity

57. Pressure (generally)
Force over Area in Pascals (Pa)
58. Hydrostatic Pressure at a fixed depth, y.
59. Buoyant Force, upward and equal to the weight of the fluid that the object displaces.

Density x volume = mass
60. The continuity equation describes volume flow rate as a function of the cross-sectional area of the pipe and the velocity of the fluid.

61. Bernoulli's Equation - pressure energy, potential energy, and kinetic energy

Pressure + Potential (density*gh) + kinetic (velocity) energies in total don't change
62. Elastic Modulus of a solid (equation)

63. 3 types of modulus of elasticity
• Young's modulus (E) for tensile stress (2 equivalent opposing parallel forces in same plane)
• Shear modulus (G) for shear stress (tensile but not lined up in same plane)
• Bulk modulus (B) for compression and expansion (forces from all sides)
• High modulus is rigid (metal and ceramic)
• Low modulus is elastic (rubber)
64. Wave velocity
65. Wave period
66. Sound Decibels

a difference of 10dB means intensity differs by a factor of 10 (90dB is 10 times louder than 80dB)
67. Standing waves - both ends fixed or free
• n=1, 2, 3, ...
• L= string or pipe length
• each end is a node or antinode
 Author: sjernst ID: 272908 Card Set: MCAT Physics Formulas Updated: 2014-05-03 14:56:51 Tags: Physics MCAT Science Folders: Description: All of the formulas for the Physics portion of the MCATs. Formula on one side and name (if applicable) with description of use on the other side. Show Answers: