Unit 5 (Ch. 8) - Momentum

momentum (p)

• inertia in motion

• An object’s momentum must depend on both its mass and velocity.

  • p=mv

impulse (J)

• quantity force × time interval

  • 𝐽 = 𝐹Δ𝑡

• The impulse acting on an object equals the change in its momentum Δ𝑝, so 𝐽 = Δ𝑝

The Law of Conservation of Momentum

• In the absence of an external force, the momentum of a system remains unchanged.

  • p_i = p_f

internal forces

Forces exchanged between members of the same system come in balanced pairs that cancel within the system

elastic collision

• When objects collide without being permanently deformed and without generating heat, the collision is an elastic collision.

• Colliding objects bounce off each other in perfectly elastic collisions.

inelastic collision

A collision in which the colliding objects become connected, distorted, or generate heat during the collision is an inelastic collision.

Whenever colliding objects become tangled or connect together, a perfectly inelastic collision occurs.

superelastic collision

The colliding objects move faster after the collision than they do before the collision.