What are the various energy transformations that occur when you are riding a bicycle?

Does the transfer of energy take place when you push a huge rock with all your might and fail to move it? Where is the energy you spend going?

An object of mass 40 kg is raised to a height of 5 m above the ground. What is its potential energy? If the object is allowed to fall, find its kinetic energy when it is half-way down.

What is the work done by the force of gravity on a satellite moving round the earth? Justify your answer.