Question

Hello! Im struggling in how to do this and im finding it difficult if someone could help me show how to solve this it would be great! (topic - physics dynamics year 11 Elastic, Collision Calculations) Thank you :>

Answer 1

A general way to approach this type of problem:

m1 v1 + m2 v2 = m1 V1 + m2 V2 conservation of momentum

1/2 m1 v1^2 + 1/2 m2 v2^2 = 1/2 m1 V1^2 + 1/2 m2 V2^2 cons energy

m1 (v1 - V1) = m2 (V2 - v1) rewriting 1st equation

m1 (v1^2 - V1)^2 = m2 (V2^2 - v2^2) rewriting second equation

(v1 - V1) (v1 + V1) = (V2 - v2) (V2 + v2) expand second equation

v1 + V1 = v2 + V2 divide second equation by first equation

This illustrates the point that relative speed of approach equals relative speed of separation in an elastic collision