Equations and Formulas

Question 1

Kinematics Equations for constant acceleration

Answer 1

v = ds/dt
s = .5(vf + vi)t
a = dv/dt
vf = vi + at
s = vit + .5at^2
vf^2 = vi^2 + 2as

Question 2

Horizontal Motion (Projectile)

Answer 2

ax = 0
vx = sx/t
sx = vxt

Question 3

Vertical Motion (Projectile)

Answer 3

ay = g = 10 m/s
vy = viy + gt
sy = viyt + .5gt^2

Question 4

Projectile Motion: How to find max height of ball?

Answer 4

First find time it takes to reach max height and then find distance (all in terms of y)

Question 5

Horizontal Motion (Projectile)

Answer 5

ax = 0
vx = sx/t
sx = vxt

Question 6

Vertical Motion (Projectile)

Answer 6

ay = g = 10 m/s
vy = viy + gt
sy = viyt + .5gt^2

Question 7

Projectile Motion: How to find max height of ball?

Answer 7

First find time it takes to reach max height and then find distance (all in terms of y)

Question 8

Static and Kinetic Friction

Answer 8

Fs = Fnus, Fk = Fnuk

Question 9

Momentum

Answer 9

p = mv

Question 10

Impulse

Answer 10

F*delta t = m * delta v = change in momentum

Question 11

Three types of conservation

Answer 11

recoil, inelastic collision, and elastic collision

Question 12

Inelastic collision

Answer 12

objects stick together. Momentum is conserved, kinetic energy is NOT

Question 13

Elastic collision

Answer 13

objects do NOT stick together. Momentum is conserved AND kinetic energy is conserved

Question 14

Equation for Work

Answer 14

W = Fd, W = fd*cos(theta) where theta is the angle between the applied force and the displacement. (J)

Question 15

Potential Energy Equation

Answer 15

W = F*d = mgh = PE = delta KE

Question 16

Kinetic Energy Equation

Answer 16

KE = .5mv^2

Question 17

Conservation of Energy Equation

Answer 17

PEi + KEi = PEf + KEf

Question 18

Power Equation

Answer 18

P = work/time (W)

Question 19

Three Centripetal Vectors

Answer 19

centripetal force, velocity, and acceleration

Question 20

Speed of an object moving in a circle

Answer 20

v = 2piR/t where R is the radius of the circle

Question 21

Centripetal Acceleration Equation

Answer 21

a = v^2/R

Question 22

Fnet equation for an object in circular motion

Answer 22

Fnet = mv^2/R

Question 23

Centrifugal vs. Centripetal

Answer 23

Centripetal force pulls an object toward the center of its circular path; centrifugal force “center-fleeing” is not a real fore but the perceived effect of inertia

Question 24

Torque Definition

Answer 24

Torque is the product of the perpendicular component of the force and the distance (r) from the rotational axis. (N*m)

Question 25

Torque in Static Equilibrium

Answer 25

F1r1 = F2r2
(m1g)r1 = (m2g)r2

Question 26

Equation for Angular Momentum

Answer 26

L = mvr

Question 27

When is Angular Momentum Conserved?

Answer 27

Angular Momentum is conserved when there are no net external torques.

Question 28

Period (T) Equation and Units

Answer 28

T = d/t, units = seconds, years, etc…

Question 29

Harmonic Motion Definition

Answer 29

An object is moving with harmonic motion if it follows a repeated path at constant time intervals.

Question 30

The period and frequency of a pendulum depend on…?

Answer 30

ONLY the length and its acceleration due to gravity. (NOT ITS MASS)

Question 31

Equilibrium position of a pendulum

Answer 31

lowest point

Question 32

Maximum displacement from equilibrium

Answer 32

amplitude

Question 33

Restoring force

Answer 33

force that is trying to restore the pendulum back toward the center of the swing. Greatest at the amplitude and zero as the pendulum passes through the equilibrium position.

Question 34

Hooke’s Law

Answer 34

Fspring = kx where x is the stretched length of the spring

Question 35

Total energy of a mass on a spring or a pendulum =

Answer 35

the sum of the potential and kinetic energies. KE + PE = total energy = a constant