A ball with a mass of 6 kg is rolling at 25 m/s and elastically collides with a resting ball with a mass of 2 kg. What are the post-collision velocities of the balls?

1 Answer
Mar 19, 2017

"The post collision velocities : "v_1^'=12,5" "m/s" , "v_2^'=37.5" "m/s

Explanation:

m_1=6" "kg
m_2=2" "kg
v_1=25" "m/s
v_2=0

v_1^'=?
v_2^'=?

"Find total momentum before collision."

"let "Sigma P_b " be total momentum before collision"

Sigma P_b=m_1v_1+m_2*v_2

Sigma P_b=6*25+2*0

Sigma P_b=150" "kg.m/s

"Now ,calculate post collision velocities."

v_1^'=(2*Sigma P_b)/(m_1+m_2)-v_1" , "v_1^'=(2*150)/(6+2)-25=12,5" "m/s

v_2^'=(2*Sigma P_b)/(m_1+m_2)-v_2" , "v_1^'=(2*150)/(6+2)-0=37,5" "m/s