Roller Coaster and Circular Motion

A roller-coaster car has a mass of 500 kg when fully loaded with passengers, as shown below.

  1. If the car has a speed of 20.0 m/s at point A, what is the force exerted by the track at this

  2. What is the maximum speed the car can have at point B and stay on the track?

Serway & Beichner, Physics for Scientists and Engineers, 5th ed., (Saunders College Publishing, 2000), p. 174