# Momentum - Physics 201 Lecture 14 Momentum Impulse...

This preview shows pages 1–7. Sign up to view the full content.

3/27/08 Physics 201, UW-Madison 1 Physics 201: Lecture 14 Physics 201: Lecture 14 Momentum Impulse Collisions: Elastic and Inelastic Conservation of Momentum and Energy

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
3/27/08 Physics 201, UW-Madison 2 Momentum and Impulse Momentum and Impulse Momentum For single object…. If F = 0, then momentum conserved ( Δ p = 0) For “system” of objects … ! F ave ! t " I definition of impulse ! F = m ! a = m d ! v dt = d ! p dt # ! ! p = ! F ! t ! p ! m ! v ! p tot = ! p i i ! Internal forces " forces between objects in system External forces " any other forces # ! p tot = ! F ext # t Thus, if ! F ext = 0, then # ! p tot = 0 i . e . total momentum is conserved!
3/27/08 Physics 201, UW-Madison 3 Collisions Collisions “before” m 1 m 2 “after” m 1 m 2 Explosions Explosions “before” M “after” m 1 m 2 Draw “before”, “after” DeFne system so that ± ext = 0 Set up axes Compute P total “before” Compute P total “after” Set them equal to each other Procedure

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
3/27/08 Physics 201, UW-Madison 4 Some Terminology Some Terminology • Elastic Collisions : collisions that conserve kinetic energy • Inelastic Collisions: collisions that do not conserve kinetic energy * Completely Inelastic Collisons: objects stick together n.b. ALL CONSERVE MOMENTUM!!
3/27/08 Physics 201, UW-Madison 5 Elastic Collision in 1-Dimension Elastic Collision in 1-Dimension m 1 v 1 i + m 2 v 2 i = m 1 v 1 f + m 2 v 2 f 1 2 m 1 v 1 i 2 + 1 2 m 2 v 2 i 2 = 1 2 m 1 v 1 f 2 + 1 2 m 2 v 2 f 2

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document