How do you find input energy with only the efficiency and output energy given?

Friction removes energy from objects in motion. which statement best describes how this works? a) friction transforms ke into thermal energy b) friction transfers thermal energy to ke c) friction transforms te into pe d) friction transforms pe into ke e) friction transfers ke into pe

Robin is swinging back and forth from a trapeze. in which of the following situations is his kinetic energy being transformed into potential energy

Difference between natural and artifical magnet