A ball with a mass of 3 kg is rolling at 11 m/s and elastically collides with a resting ball with a mass of 4 kg. What are the post-collision velocities of the balls?

1 Answer
Feb 27, 2016

"see to animation"
v_r=-11/7 m/s
v_y=66/7 m/s

Explanation:

enter image source here
m_r:" mass of the red ball"
m_y:" mass of the yellow ball"
v_r:" velocity of the red ball after collision"
v_y:" velocity of the yellow ball after collision"
3*11+0=3*v_r+4*v_y
33=3*v_r+4*v_y" (1)"
11+v_r=0+v_y" (2)"
v_y=11+v_r" (3)"
"insert (3) into (2)"
33=3*v_r+4*(11+v_r)
33=3*v_r+44+4*v_r
33-44=7*v_r
-11=7*v_r
v_r=-11/7 m/s
"use (3):"
v_y=11-11/7
v_y=66/7 m/s