A 61 kg skateboarder riding the board falls off and tumbles with a kinetic energy of 45 Joules. What is his velocity?

1. most waves are caused by vibrations. what motion in a transmitting antenna causes the vibrations that produce radio waves? 2. name two common household appliances that produce electromagnetic waves other than radio waves. what kind of electromagnetic waves do they produce? 3. when you are in a car and it passes through a tunnel, the radio signal is sometimes lost. why do you think this happens?

The summit of chimborazo, in ecuador, which is at a distance of about 6,384 km from the earth's center. the bottom of the mariana trench, in the western pacific ocean, which is nearly 6,370 km from the center of the earth. on the surface of earth on the equator line.

A150 w lamp emits light of wavelength 590 nm uniformly in all directions. what is the photon flux (photons per unit area per unit time) on a small screen at a distance 2.3 m from the lamp? assume the photons are uniformly distributed over the surface of a sphere of radius 2.3 m.