During a football game, a receiver has just caught a pass and is standing still. Before he can move, a tackler, running at a velocity of 3.70 m/s, grabs and holds onto him so that they move off together with a velocity of 2.00 m/s. If the mass of the tackler is 123 kg, determine the mass of the receiver. Assume momentum is conserved.

W= fd
where f is an applied force and d is the distance over which it is applied. when a parachuting skydiver is at constant velocity, he is experiencing "terminal velocity", the point at which his acceleration down is canceled out by air resistance. that means that the resisting force of the air is equal to his weight, but in the opposite direction. with this, we can solve for the work done by the force.
w = fd
w = (92.0)(9.81 m/s^2) (325)
w= 2.93 x 10^5 j
the value for work in this case is positive because it is pushing up on the skydiver, who has a downward force of gravity.
therefore the answer is 2.93 x 10^5 j

45 is the correct answer