So does this mean that n = -mg, so
m * a_c = 2mg ?
a_c = 2ga_c = 19.6
v^2/r = 19.6
v^2 = 19.6 * 4 = 78.4
v = 8.85
9.8 * h = 1/2 * 9.85^2 + 8 * 9.8
x = 12.95
Hmm.. this is closer, but still not correct.
Homework Statement
Part of a roller-coaster ride involves coasting down an incline and entering a loop 8.00 m in diameter. For safety considerations, the roller coaster speed at the top of the loop must be such that the force of the seat on a rider is equal in magnitude to the rider's weigt...