bold indicates a vector
time independent kinematics equation
vf2 = vo2 + 2ax
net force (Newton’s second law)
∑F = ma
force in terms of momentum (Newton’s 2nd law as a derivative)
F = dp/dt
force in terms of potential energy
F = -dU/dx
impulse
J = ∫F dt
definition of momentum
p = mV
impulse - momentum theroem
J = ∆p
force of friction
Fƒ ≤ µFN
work done by a constant force (dot product)
W = F * d
work done by a variable force (integral)
W = ∫F * ds
kinetic energy (linear)
EK = (1/2)mv2
work - energy theorem
Wnet = ∆Ek
power (as a rate of change)
P = dW/dt
power (dot product)
P = F * v
centripetal acceleration
ac = v²/r = ω2r
torque (cross product)
τ = r x F
Newton’s second law for rotation (torque and angular acceleration)
∑τ = Iα
moment of inertia of a collection of particles (no integral)
I = ∑miri2
parallel axis theorem
I‖ = Icom + mh²
rotational inertia of a rod about an axis through its center
Irod = (mℓ2)/12
/ ℓ is not a vector
angular momentum of a moving particle (cross product)
ℓ = r x p
/ ℓ is a vector
angular momentum of a rigid rotation body (rotational inertia)
L = Iω
position of a center of mass for a collection of particles (sigma notation)
rcom = (∑miri)/M
conversion between linear and angular velocity (no slip)
ω x r = V → V = rω
rotational kinetic energy
Ek = (1/2)Iω2
force of a spring (Hooke’s law)
F = -kx
potential energy of a spring
Uspring = (1/2)kx2
period of a spring mass system
T = 2π √(m/k)
angular frequency of a general pendulum
ω = √(MgD/t)
period of a simple pendulum
T = 2π √(ℓ/g)
/ ℓ is not a vector
relationships between period, frequency, and angular frequency
1/T = ƒ = ω/(2π)
Newton’s law of gravitation
FG = (Gm1m2)/r²
gravitational potential energy
UG = (-Gm1m2)/r
total mechanical energy of an object in circular orbit
Utotal = (-Gm1m2)/2r
Kepler’s 3rd law
(τ2)/(r3) = (4π2)/(GMs)
/ note: r is average of rmin and rmax
escape velocity
vescape = √((2GMe)/Re) = √(2Reg)