1. A 1.4 x 103kg car is westbound at a velocity of 37.0 km/h when it collides with a 2.0 x 10kg truck northbound at a velocity of 35 km/h. If these two vehicles lock
together upon collision, what is the initial velocity of the vehicles after collision?

This is the answer: body 1 + engine 2

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