A roller-coaster car speeds down a hill past point A and then rolls up a hill past point B. The car has a speed of 16.1 m/s at point A. The acceleration of gravity is 9.81 m/s^2. Radius of Circle A is 9.98 m. Radius of Circle B is 15.5 m.

Question

A roller-coaster car speeds down a hill past point A and then rolls up a hill past point B. The car has a speed of 16.1 m/s at point A. The acceleration of gravity is 9.81 m/s^2. Radius of Circle A is 9.98 m. Radius of Circle B is 15.5 m.
a) If at point A the track exerts a force on the car that is 2.93 × 10^4 N greater than the car’s weight, what is the mass of the car? Answer in units of kg. 
b) What is the maximum speed the car can have at point B for the gravitational force to hold it on the track? Answer in units of m/s.

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