Bobby does work to climb to the top of a 7 m hill. If Bobby and his sled have a combined mass of 45 kg, how much Potential Energy will Bobby have at the top of the hill? (Ignore friction in this problem.)

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.

The crank oa rotates in the vertical plane with a constant clockwise angular velocity ω0 of 5.6 rad/s. for the position where oa is horizontal, calculate the force under the light roller b of the 10.6-kg slender bar ab.

When a light bulb shines, it gives off light energy and energy. a. heat b. potential c. chemical d. electrical