To summarize, potential energy is the energy that is stored in an object due to its position relative to some zero position.
Holding a bow and arrow before shooting, The amount of energy stored before you race on track, And a roller coaster going to it's highest point staying there waiting to come down.
The swimmer swims 50 meters to one end of the pool but has to swim back therefore you double 50 which would be 100 meters. Then you have to multiply 100 by 4 since the swimmer did it 4 times.
It can't be less than 250 N or the cart wouldn't move at all. That means there is only 1 answer. It's between not enough info or 250 N. The answer is 250 N. If it was any more, there would be acceleration.
