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?

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Answer 1 · 2018-06-23T18:10:03

The velocity of the second ball after the collision is #=1.17ms^-1#

#m_1u_1+m_2u_2=m_1v_1+m_2v_2#

The mass the first ball is #m_1=7kg#

The velocity of the first ball before the collision is #u_1=3ms^-1#

The mass of the second ball is #m_2=18kg#

The velocity of the second ball before the collision is #u_2=0ms^-1#

The velocity of the first ball after the collision is #v_1=0ms^-1#

Therefore,

#7*3+18*0=7*0+18*v_2#

#18v_2=21#

#v_2=21/18=1.17ms^-1#

The velocity of the second ball after the collision is #v_2=1.17ms^-1#