A man strikes a nail into a wooden block, with an average force of 200N. If he continues to strike the nail with that force, estimate how much heat energy will be generated by the time the nail penetrates a depth of 0.05m?​

Light traveling in water, nwater = 1.33, strikes a plastic block at an angle of incidence of 51.4°; part of the beam is reflected and part is refracted. if the index of refraction of the plastic is 2.0, what is the angle made by the reflected and refracted beams?

If a star is moving toward earth, it is

Which describes increasing the efficiency of energy resource