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

Acave rescue team lifts an injured spelunker directly upward and out of a sinkhole by means of a motor-driven cable. the lift is performed in three stages, each requiring a vertical distance of 10.0 m: (a) the initially stationary spelunker is accelerated to a speed of 4.90 m/s; (b) he is then lifted at the constant speed of 4.90 m/s; (c) finally he is decelerated to zero speed. how much work is done on the 68.0 kg rescue by the force lifting him during each stage?

What is the primary force that suspension bridges use cables to hold their spans up? a. tension force b. resistance force c. normal force d. elastic force e. applied force

What describes the formation of horizon b? a. forms at the surface b. features parent material c. undergoes the most change d. forms due to decomposed material i think the answer is c. undergoes the most change