Question

In a football game, a receiver is standing still, having just caught a pass. Before he can move, a tackler, running at a velocity of +3.1 m/s, grabs him. The tackler holds onto the receiver, and the two move off together with a velocity of +1.6 m/s. The mass of the tackler is 115 kg. Assuming that momentum is conserved, find the mass of the receiver.

Answer 1

Answer:

$m_{receiver}=115Kg*3.1/(1.6)-115Kg=107.8Kg$    

Explanation:

The football players collide in a completely inelastic collision, in other words they have the same velocity after the collision, this velocity has a magnitude V=1.6m/s.

We need to use the conservation of momentum Law, the total momentum is the same before and after the collision, at the initial point the receiver does not have any speed

$m_{tackler}*v_{tackler}=(m_{tackler}+m_{receiver})V$     (1)

We solve in order to find the receiver mass:

$m_{receiver}={m_{tackler}*v_{tackler}/V}-m_{tackler}$    

$m_{receiver}=115Kg*3.1/(1.6)-115Kg=107.8Kg$