Question

A 25-kg child sits at the top of a 4-meter slide. After sliding down, the child is traveling at 5 m/s. How much PE does he start with? How much KE does he end with? How much energy is lost to friction?

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Answer 1

potential energy = mass× gravity × height (PE= mgh)
PE = 25 × 10 × 4 (am taking gravity to be 10 m/s^2....it could also be 9.81)
PE = 1000 J

Kinetic energy = (1÷2) mass × speed^2
EK = 0.5 × 25 ×5^2
EK= 312.5 J

energy LOSS DUE TO FRICTION IS 1000 - 312.5 = 687.5J (If I made no error in calculations)