What types of energy does a ball rolling down a hill have?

How much work is done lifting a 9.10 kg box straight up onto a shelf that is 1.80 m high?

If a star is moving toward earth, it is

Would it be correct to say the doppler effect is the apparent change in the speed of a wave due to the motion of the source? be sure to fully explain your position using at least 3 complete content related sentences.