Question

A 20 kg kid jumps from a moving swing. When she leaves the swing she is y1=1.0 m above the ground, moving with a speed v1=2 m/s at an angle 60 degrees above horizontal.

(a) What is the change in potential energy (∆U) as she moves from the swing to the ground (y =0 m)?

(b) Use conservation of mechanical energy (∆K + ∆U = 0) to find her speed as she reaches the ground.

(c) What is the change in her kinetic energy (∆K) as she moves from the swing to her maximum height? Remember, vy = 0 at her maximum height, but she has kinetic energy there because she is still moving – the x component of her velocity has not changed.

(d) Use conservation of mechanical energy to find the maximum height above the ground that she reaches after jumping from the swing.

Answer 1