Assuming luke has a mass of 90kg how much potential energy does he have just as he leaves the plane 7620 meters up? explain how you know.

What is the frequency of a light wave with a wavelength of 620nm

Atrain departs from its station at a constant acceleration of 5 m/s. what is the speed of the train at the end of 20s?

Afisherman notices that his boat is moving up and down periodically without any horizontal motion, owing to waves on the surface of the water. it takes a time of 2.20 s for the boat to travel from its highest point to its lowest, a total distance of 0.670 m . the fisherman sees that the wave crests are spaced a horizontal distance of 5.80 m apart. (a) how much is the wavelength? (b) find the period of the wave. (c) how fast are the waves traveling? (d) what is the amplitude a of each wave?