Question

Two hockey players of opposite teams, while trying to hit a hockey ball in the ground collide and immediately get entangled. one has a mass of 60kg and is moving with a velocity 5m/s, while the other has a mass of 55kg and is moving faster with a velocity of 6m/s toward the first player. In which direction and with what velocity will they move after they get entangled? Assume the frictional force between the feet of the two players and the ground is negligible.

Answer 1

Here, m1=60kg,u1=5.0m/s,m2=55kg,u2=−6.0m/s

Negative sign with u2 indicates that direction of second player is opposite to the direction of the first player. If v is the combined velocity of the two players, then applying the principle of conservation of linear momentum,

we get (m1+m2)v=m1u1+m2u2 or (60+55)v=60×5.0+55(−6.0)

or 115v=300−330=−30 or v=−30115=−0.26m/s

Negative sign shows that the combined velocity of the two players is in the direction of the second player.