Question

Will pushing on a car always change the cars mechanical energy?what must happen for the cars kinetic energy to increase?

Answer 1

1) Pushing on a car will not always change the car's mechanical energy, but it does change yours since your physically using most of your energy to push the car.
 
2) In order for a cars kinetic energy to increase, the car has to be in motion when it is going down a hill, because when you go down hills and objects like that; you tend to increase in kinetic energy.

Answer 2

Answer:

Explanation:

For a car to have a change in mechanical energy, it should be moving on its own. In this case a person is pushing a car, this will not change the mechanical energy of the car.

For a car to gain the kinetic energy, it must acquire a speed. If the car is standing on a hill and you are applying force on from upward direction, it will get attracted due to gravity and thus will acquire a speed which will enhance its kinetic energy.