A ball with a mass of #7 kg# moving at #3 m/s# hits a still ball with a mass of #18 kg#. If the first ball stops moving, how fast is the second ball moving? How much heat energy was lost in the collision?

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Answer 1 · 2016-11-02T08:51:18

By momentum conservation ,

#P_i=P_f#------[where #P= momentum= mass xx velocity#]

Let the velocity of ball with mass 10 kg be 'v'.

#7 xx 3+18 xx 0 = 7 xx 0 + 18 xx v#

#21=18v#

#v=21/18#

#v= 1.16m/s#

Loss in kinetic energy = KE_i - KE_f#

Loss in kinetic energy = #1/2 xx 7xx 3- 1/2 xx 18 xx 1.16xx1.16 #

Loss in kinetic energy = #10.5 - 12.11#

Loss in kinetic energy = #1.61# Joule