Question

a body British moving with a velocity of 20ms(power -1) collides with another body A, moving in the same direction on the same horizontal line with a velocity of 10ms (power -1).if the mass of the body A is three times the mass of body B, and the collision is perfectly elastic. calculate the velocity of A and B after the collision and the velocity of B relativemail to that of A after the collision

Answer 1

I am not going to do all the math.
Conservation of momentum, and energy applies
Momentum
A*20+B*10=A*Va + B*Vb
but A=3B
Energy:
1/2 A 20^2+1/2 B*10^2=1/2 A Va^2 + 1/2 B Vb^2

in equation 1, solve for Va in therms of all else, then substiture it in equation 2, and solve the quadratic.