A moving object has kinetic energy. The amount of kinetic energy possessed by a moving object can be determined if we know the mass of the object and the velocity of the object.
Kinetic energy = 1/2 mv^2
where, m is the object's mass and v is its velocity.
If the object is moving at a constant elevation, kinetic energy may be the only energy possessed by an object. However, for an object moving down from a uphill location to a downhill location (that is, along a slope), the object possesses both the potential energy and the kinetic energy. Think of water falling down from the top of a dam to the turbines placed at the bottom of the dam. The potential energy stored in the water (due to its height) is being converted to kinetic energy during the motion (and it is this original potential energy that is converted to electricity in the hydropower plants).
Hope this helps.