A roller-coaster car speeds down a hill past point A where R1 = 8.0 m and then rolls up a hill past point B where R2 = 14.0 m.
The car has a speed of 21.0 m/s at point A. if the track exerts a normal force on the car of 2.19 multiplied by 104 N at this point, what is the mass of the car?
I don't understand what R1 and R2 are. Are they heights?
R1 and R2 are both the radius of the circles at the bottom and top respectively. I don't know the answer, I'm looking into that as well. At least you know that it's a radius now! :D