The normal force equals the magnitude of the gravitational force as a roller coaster car crosses the top of a 58-m-diameter loop-the-loop. What is the car's speed at the top?

16.87 m/s

Explanation:

To find the speed of the car at the top, when the normal force is equal the gravitational force, we just need to equate both forces:

is the centripetal acceleration in the loop:

So we have that:

So, using the gravity = 9.81 m/s^2 and the radius = 29 meters, we have:

The speed of the car is 16.87 m/s at the top.

the displacement produced by the body.  

the amount of force subjected to the body.  

the angle between the direction of force and displacement