impulse/momentum problem #2?

Question

Louise is riding in a roller coaster. Louise experiences a downward acceleration of 25.0 m/s2 at the top of the loop and an upward acceleration of 30.0 m/s2 at the bottom of the loop. Use Newton’s second law to determine the normal force acting upon Louise’s 1000 kg roller coaster car

Answer 1

W - the weight (i.e. force due to gravity) - constant
N - the normal force exerted by the track. - variable

At the top of the loop, both forces are pointing down and the result gives a specified acceleration At.

Ft = Nt + W = M x At

At the bottom, gravity is still pointing down, but the normal force is pointing up and is larger:

Fb = Nb - W = M x Ab

Since W = M x g (the gravitational acceleration - about 9.8 m/s^2 at the surface of the Earth), and we know the values of At and Ab, we can compute Nt and Nb.