A ball with a mass of #5# #kg# moving at #2# #ms^-1# hits a still ball with a mass of #6# #kg#. If the first ball stops moving, how fast is the second ball moving?

1 Answer
Apr 22, 2016

#v_2=5/3 m/s#

Explanation:

#"Total momentum before collision:"#
#....................................................#
#P_1=m_1*v_1" "P_1=5*2=10#
#P_2=m_2*v_2" "P_2=6*0=0#
#Sigma P_b=P_1+P_2#
#Sigma P_b=10+0#
#Sigma P_b=10 kg*m/s#

#"Total momentum after collision:"#
#..................................................#
#P_1=5*0" "P_1=0#
#P_2=6*v_2#
#Sigma P_a=P_1+P_2#
#Sigma P_a=0+6*v_2#
#Sigma P_a=6*v_2#

#"Conservation of momentum"#
#............................................#
#Sigma P_b=Sigma P_a#
#10=6*v_2#

#v_2=10/6#

#v_2=5/3 m/s#