Six roller-coaster carts pass over the same semicircular "bump." The mass M of each cart (including passenger) and the normal force n of the track on the cart at the top of each bump are given in the figures.

Rank the speeds of the different carts as each passes over the top of the bump.

(a) F=300N, M=300kg
(b) F=800N, M=800kg
(c) F=400N, M=200kg
(d) F=200N, M=400kg
(e) F=800N, M=100kg
(f) F=400N, M=100kg

[Solution]
The net force of the system supply the centripetal force.

The speed of each cart is

Order is (d)>(a)=(b)>(c)>(f)>(e)