Physics

# Key Equations

PhysicsKey Equations

## 8.1Linear Momentum, Force, and Impulse

 impulse $F net Δt F net Δt$ impulse–momentum theorem $Δp= F net Δt Δp= F net Δt$ linear momentum $p=mv p=mv$ Newton’s second law in terms of momentum $F net = Δp Δt F net = Δp Δt$

## 8.2Conservation of Momentum

 law of conservation of momentum ptot = constant, or ptot = p′tot conservation of momentum for two objects p1 + p2 = constant, or p1 + p2 = p′1 + p′2 angular momentum L = I $ω ω$

## 8.3Elastic and Inelastic Collisions

 conservation of momentum in any collision, including elastic collisionselastic collision $m 1 v 1 + m 2 v 2 = m 1 v ′ 1 + m 2 v ′ 2 , m 1 v 1 + m 2 v 2 = m 1 v ′ 1 + m 2 v ′ 2 ,$ conservation of momentum in a perfectly inelastic collision conservation of momentum along x-axis for 2D collisions $m 1 v 1 = m 1 v ′ 1 cos θ 1 + m 2 v ′ 2 cos θ 2 m 1 v 1 = m 1 v ′ 1 cos θ 1 + m 2 v ′ 2 cos θ 2$ conservation of momentum along y-axis for 2D collisions $0= m 1 v ′ 1 sin θ 1 + m 2 v ′ 2 sin θ 2 0= m 1 v ′ 1 sin θ 1 + m 2 v ′ 2 sin θ 2$