physics 3!!**
posted by kelsey .
In a football game, a tackle running at a constant speed of 5 m/s tackles a stationary receiver. The two fly off horizontally at 4 m/s, before they hit the ground and begin to slow down. If the mass of the tackle is 120 kg,
a.) What is the mass of the receiver?
b.) Calculate the kinetic energy of the tacklereceiver system before and after the collision.
KEsys, i = J
KEsys, f = J

Momentum is conserved.
Momentum before = MassTackle*5
momentum after =(masstackle+massreceiver)4
set them equal, you know themass of the tackle, solve for massreceiver.