Question

Writing an EEI on the efficiency of a crash between two hotwheels cars. What formula would I need to find the efficiency? (I know nothing)

Answer 1

If by efficient, you mean the elasticity of the collision, you'd want to use the following two equations:\[\epsilon ( m _{1}v _{1a}+m _{2}v _{2a})=m _{1}v _{1b}+m _{2}v _{2b}\]where m1 is the mass of car 1; v1a is the initial velocity of car 1; m2 is the mass of car 2; v2a is the initial velocity of car 2; v1b is the final velocity of car 1; v2b is the final velocity of car 2; and ε is the coefficient of restitution ( a measure of elasticity) for the collision.

The other equation would be:\[\frac{ 1 }{ 2 }\epsilon ^{2}\left(m _{1}v _{1a}^{2}+m _{2}v _{2a}^{2} \right)=m _{1}v _{1b}^{2}+m _{2}v _{2b}^{2}\]with the variables being defined as they were in equation #1.