A ball with a mass of # 3 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 4, 2016

Answer:

#v_1^'=5" " m/s#
#v=2^'=30" " m/s#

Explanation:

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#m_1*v_1+0=m_1*v_2^'+m_2*v_2^' " Conversation of momentum"#
#3*25+0=3*v_1^'+2*v_2^'#
#75=3*v_1^'+2*v_2^' " "(1)#
#v_1+v_1^'=v_2+v_2^'" "(2)#
#25+v_1^'=0+v_2^'" "v_2^'=25+v_1^'" "(3)#
#75=3*v_1^'+2(25+v_1^')#
#75=3*v_1^'+50+2v_1^'#
#75-50=5v_1^' " "25=5v_1^'" "v_1^'=5" " m/s#
#use (3):#
#v_2^'=25+5#
#v=2^'=30" " m/s#