Question

unit 2 exam mcq portion (10 question version)
(a) $\frac{rg}{v^{2}}$
(b) $\frac{mv^{2}}{r}$
(c) $\frac{v^{2}}{g}$
(d) $\frac{v^{2}}{rg}$
(e) $\frac{v^{2}}{2rg}$
10.
the car is now going around a banked curve, as shown in the figure above. the banked curve is higher toward the outside of the circular turn. the car can now travel at a higher speed without sliding because the banked curve
(a) increases the coefficient of friction between the car and the track.
(b) increases the momentum of the car.
(c) allows a component of the normal force to point toward the center of the track.
(d) allows a component of the weight of the car to point toward the center of the track.
(e) allows gravity to do work on the car.

Explanation:

When a car is on a banked - curve, the normal force acting on the car has a horizontal component. This horizontal component of the normal force provides the necessary centripetal force for the car to move in a circular path. The coefficient of friction is a property of the surfaces in contact and is not increased by banking the curve (eliminating A). Banking the curve does not increase the momentum of the car (eliminating B). The weight of the car acts vertically downwards and banking does not make a component of the weight point towards the center of the track (eliminating D). Gravity does work on the car when there is a vertical displacement, which is not relevant to the centripetal - force requirement for circular motion on a banked curve (eliminating E).

Answer:

C. allows a component of the normal force to point toward the center of the track.