5. Bill has a mass of 70 kg and is running. He collides with Ethel, who is sitting in a chair with wheels. Ethel's mass is 50 kg. Bill falls into Ethel's lap and they both go rolling at 5 m/s. How
fast was Bill running before the collision?

the motion of a pendulum is a classic example of mechanical energy conservation. a pendulum consists of a mass (known as a bob ) attached by a string to a pivot point. as the pendulum moves it sweeps out a circular arc, moving back and forth in a periodic fashion.

i think its c if i'm wrong

at right angles to each other

the answer is c. the lower legs are levers, and the knees are fulcrums. the ankles hold the loads.