A child holds a ball of mass m a distance h above the ground. Check all of the following statements that describe potential energy correctly in this case. (Assume potential energy is zero when the ball is on the ground.)
1. The ball alone has potential energy mgh.
2. The system of the earth and the ball together have potential energy mgh

Name three different units of energy used to measure heat and describe what type of situations each is usually used.

Awater-filled u-tube manometer is used to measure the pressure inside a tank that contains air. the water level in the u-tube on the side that connects to the tank is 5 ft above the base of the tank. the water level in the other side of the u-tube (which is open to the atmosphere) is 2 ft above the base. determine the pressure within the tank.

A"car"initially"at"rest"experiences"a" constant"acceleration"along"a"horizontal" road."the"position"of"the"car"at"several" successive"equal"time"intervals"is" illustrated"here. between"which"adjacent"positions"is"the" change"in"kinetic"energy"of"the"car"the" greatest