Which of the following is a physical change? a. sawing a piece of wood in half b. burning a piece of wood c. rust forming on an iron fence d. a copper roof changing color from red to green

A0.580-kg rock is tied to the end of a string and is swung in a circle with a radius of 0.500 meters. the velocity of the rock is 4.50 m/s. what is the centripetal force acting on the rock? 15.5 n 5.22 n 69.8 n 23.5 n