50 j of work was performed in 20 seconds. how much power was used to do this task? a. 0.4 w b. 2.5 w c. 4 w d. 24.5 w

Within a pendulum, as potential energy decreases, energy increases. a. heat b. kinetic c. frictional d. gravitational

Air is contained in a variable-load piston-cylinder device equipped with a paddle wheel. initially, air is at 400 kpa and 17°c. the paddle wheel is now turned by an external electric motor until 75 kj/kg of work has been transferred to air. during this process, heat is transferred to maintain a constant air temperature while allowing the gas volume to triple. calculate the required amount of heat transfer in kj/kg.

The force needed to overcome static friction is usually less than that needed to overcome kinetic friction.true or false?