# A metal ball of mass 2 kg moving with speed of 36km/h is having a collision with a stationary ball of mass 3kg. If after collision, both the balls move together, the loss in kinetic energy due to collision is    Option 1) 80 J  Option 2) 40 J  Option 3) 60 J  Option 4) 160 J

As we discussed in concept

If only conservative forces act on a system, total mechnical energy remains constant -

$K+U=E\left ( constant \right )$

$\Delta K+\Delta U=0$

$\Delta K=-\Delta U$

-

$\Delta k=\frac{1}{2}(\frac{m_{1}m_{2}}{m_{1}+m_{2}})u_{1}^{2}$

on putting the value we get 60J

Option 1)

80 J

Option is incorrect

Option 2)

40 J

Option is incorrect

Option 3)

60 J

Option is correct

Option 4)

160 J

Option is incorrect

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