Problem 3- A 10-g metal ball is moving to the left with a velocity of magnitude 0.4 m/s has a head-on, elastic collision with a larger 30-g metal ball moving to the right with a velocity of magnitude 0.2 m/s.

Question

a) Find the speed of the two balls after the collision.
b) If the 10g ball is made of mud that stich with the 30g ball after the collision. What is the final speed of the taw ball, and the direction of motion?

Answer 1

If it is elastic, not only momentum is the same before and after but also kinetic energy

If they stick together, then only momentum is conserved but the single mass after collision is m1 + m2

part a
m1 Vi = m1 u + m2 v
(1/2)m1 Vi^2 = (1/2)m1 u^2 +(1/2)m2 v^2

part b
m1 Vi = (m1+m2) v