A ball with a mass of 2 kg is rolling at 5 m/s and elastically collides with a resting ball with a mass of 1 kg. What are the post-collision velocities of the balls?

1 Answer
May 18, 2016

v_1^'=5/3 m/s

v_2^'=20/3 m/s

Explanation:

"Before Collision :"
m_1=2kg
v_1=5m/s
P_1=m_1*v_1" "P_1=2.5=10 kg*m/s

m_2=1kg
v_2=0
P_2=m_2*v_2" "P_2=1*0=0

"Total Momentum before Collision :"

Sigma P_b=P_1+P_2" "Sigma P_b=10+0 " "Sigma P_b=10 kg*m/s

"Post collision velocities :"

v_1^'=(2*P_b)/(m_1+m_2)-v_1

v_1^'=(2*10)/(2+1)-5

v_1^'=20/3-5" "v_1^'=(20-15)/3" "v_1^'=5/3 m/s

v_2^'=(2*P_b)/(m_1+m_2)-v_2

v_2=(2.10)/(2+1)-0

v_2^'=20/3 m/s