General Physics I - Exam 2

Momentum

p→ = mv

(momentum = mass×velocity)

• momentum is a vector

• units are kg×m/s

Impulse

J→ = FΔt

• impulse is a vector

• units are kg×m/s

Translational kinetic energy

K = 1/2mv²

Elastic potential energy

Eₚ = 1/2kx²

Gravitational potential energy

U = mgy

Work energy theorem

Wₙₑₜ = ΔKE

Work done by nonconservative forces

Wₙ꜀ = ΔKE + ΔPE

Work

W = Fcosθd

Hooke’s Law

F = -kx

Conservation of Mechanical Energy

KE₁+ PE₁ = KE₂ + PE₂

Relative motion

mv = m₁v₁ + m₂v₂

Definition of power

P = w / Δt

• rate at which work can be delivered

• unit = Watts

Alternate power formula

P = Fv

Impulse momentum theorem

J = Δp = 2mvsinθ

Final kinetic energy when object starts from rest

KE₂ = mgd - Fd

Average power during displacement

Pₐᵥ = -F √(KE₂/2m)

Initial velocity of falling object

v₀ = √(v² + 2gΔy)

Initial compression of a spring, Δℓ

Δℓ = √(m/k) × v₀