Question

A car travels around a loop with negligible friction at a constant speed and never loses contact with the loop. The top of the loop is labeled A and the bottom of the loop is labeled B.

(a) At what point would the normal force be greatest? Briefly explain your reasoning.
a) A
b) B
c) Normal force is the same at all points
d) Normal force depends on the car's speed

Answer 1

The normal force is greatest at point B (the bottom of the loop) because at this point, it has to counteract both the car's weight and provide the centripetal force for circular motion.

Step-by-step explanation:

The student asked: At what point would the normal force be greatest for a car traveling around a loop at a constant speed? The answer is b) B, which is the bottom of the loop.

This is because at the bottom of the loop, the car experiences both the force of gravity and the centripetal force required to keep it moving in a circle.

Therefore, the normal force from the track must not only counteract the weight of the car but also provide the centripetal force necessary to maintain its circular motion. Because the normal force must fulfill these two requirements, it is greatest at the bottom of the loop (point B).