Hydraulics uses to change the size and/or direction of a force

How much work is done lifting a 9.10 kg box straight up onto a shelf that is 1.80 m high?

A10.0 kg cart and a 15kg cart are locked together with a compressed spring between them. they are then released so that the spring pushes the two carts apart. the 10.0 kg cart is moving at 4.5 m/s afterward. how fast is the 15kg cart moving? 3.0 m/s 2.0 m/s 4.5 m/s 5.0 m/s

When the force acting on an object points at least partially in the direction of the motion the work done is considered to be negative