A ball with a mass of #2 kg# is rolling at #3 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 19, 2016

Answer:

#v_1^'=1" m/s"#
#v_2^'=4 " "m/s#

Explanation:

#Sigma vec P_b=m_1*vec v_1+m_2*vec v_2#
#Sigma vec P_b=2*3+1*0#
#Sigma vec P_b=6 kg*m/s" Total momentum before collision"#

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

#v_1^'=(2*6)/(2+1)-3#

#v_1^'=12/3-3#

#v_1^'=4-3=1 " "m/s " velocity of "m_1 " after collision"#

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

#v_2^'=(2*6)/(2+1)-0#

#v_2^'=4 " "m/s" velocity of " m_2 " after collision"#