Gravitational potential energy, kinetic energy and mechanical energy
Explanation:
The body is at a displacement to the gravity and therefore has energy stored in it as a result of its displacement against gravity. When this body is released the gravitational potential energy is converted to translational kinetic energy as well as rotational kinetic energy as it rolls down the the ramp. The sum of the kinetic energies and potential energy of the body amount to the mechanical energy of the ball down the ramp.
Zero acceleration means the object's velocity is not changing. So the object is moving in a straight line, at a constant speed that could be anything (including zero) as long as it's constant.
