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

Answer:

#"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#