Question

give reason that why in a roller coaster the potential and kinetic energy keep on changing

Answer 1

in a lawn roller coaster potential energy as well as kinetic energy both keep changing because because a roller coaster is moving up and down so when it reaches height it has some potential energy and when is come down it uses of potential energy to potential energy change at height change and kinetic energy change because it is coming down its speed increases and as it is going up its speed decreases a little so we can say that potential energy as well as kinetic energy both are changing on a roller coaster

Answer 2

Kinetic energy is directly proportional to square of velocity.
Since roller coaster is somewhat round and zig zag like, therefore its velocity changes at every instant therefore its KE changes
Since its height also changes ,therefore potential energy =mgh changes