Why do planets revolve around the sun?​

A500g object falls off a cliff and losers 100 j from its gravitational potential energy store. if the gravitational field strength g=9.8n/kg, how high is the cliff?

An object is 10 cm from the mirror, its height is 1 cm and the focal length is 5 cm. what is the image height? (indicate the object orientation by including the + or - sign with the answer.) hi = cm +1 -1 +10 -10

The transfer of heat through the movement of a gas or liquid a. convection b. conduction c. radiation