If you have two objects on the edge of a cliff, how can you determine which one has the most potential energy?

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

Anybody wanna ? (picture included? )

The mini-refrigerator fire was most likely caused by what type of wiring?