A meatball rolls off a table and falls on the floor. Is work done or not done?
A crane lifts a steel beam to the top of a building.
Is work done or not done?

Why does lightning travel from clouds to the ground?

Two cannon balls weighing 18 kg and 24 kg are chained together and fired horizontally with a velocity of 165 m/s from the top of a 21-m wall. the chain breaks during the flight of the cannonballs and the 18-kg cannonball strikes the ground at t = 1.5 s, at a distance of 240 m from the foot of the wall, and 7 m to the right of the line of fire. determine the position of the other cannonball at that instant. neglect the resistance of the air.

Listed following are various physical situations that describe how light interacts with matter. match these to the appropriate category. 1) transmission? -visible light meets clear glass -visible light does not pass through a black wall -red light hits a red sweatshirt -light comes from your computer screen -cell phone signals pass through walls -blue light hits a red sweatshirt -white light hits a white piece of paper -light comes from a light bulb