Choose the letter of the best description of the nature of light: a. light always behaves like waves. b. light always behaves like particles. c. light sometimes behaves like waves and at other times like particles. d. light never behaves like either waves or particles.

Apulley system is used to lift a 2,000 newton engine up a distance of 3 meters. the operator must apply a force of 250 newtons to the chain of the pulley system to lift the motor. to lift the engine 3 meters, the operator must pull a total of 30 meters of chain through the pulley system. what is the value of di?

Of is j/kg·k. if a 2.6 kg of isk to k, is ?

A51 kg woman skis down a hill and her kinetic energy is 9.96e4 j. what is her speed?