A car drives around a horizontal, circular track at constant speed. Consider the following three forces that act on the car: (1) The upward normal force exerted on the car by the road, (2) the downward gravitational force on the car, (3) and the frictional force that is directed toward the center of the circular path.

Which of these forces does zero work on the car as the car moves along the circular path? 1, 2, and 3 3 1 and 2
1 2 1 and 3
2 and 3

By definition, work, is the process through which a force, applied on an object, produces a displacement of this object, and can be expressed as the dot product of the force vector and the displacement vector.

It can be also understood as the projection of the force in the direction of the displacement, so, if both vectors are perpendicular, as the projection of one vector along the other is nul, if a force and the displacement are perpendicular, no work is done.

In our case, the 3 forces mentioned, are perpendicular respect the displacement.

For normal force and gravity, as they act vertically, and the car moves along an horizontal trajectory, both are perpendicular, so no work is done.

For the friction force, as it is the only horizontal force present, it is just the centripetal force that keeps the car moving in a circular path.

It always aims to the center of the circle, along the radius at any point, so it is always perpendicular to the displacement also.

hamzaahmeds hamzaahmeds · Answer 2 · 2021-10-24T12:47:02+02:00

This question involves the concepts of zero work, friction force, centripetal force, normal force, and gravitational force.

The forces that do zero work on the car as the car moves along the circular path, are "1, 2, and 3".

The work done is defined as the product of the displacement and the component of the force in the direction of the displacement.

[tex]W = FdCos\theta[/tex]

Hence, the condition of zero work requires the angle to be 90° (perpendicular).

The upward normal force and the gravitational force both act in the vertical plane, while the motion of the car is in the horizontal plane. Therefore, the forces are perpendicular to the motion and they do zero work.

The frictional force directed towards the center of the circular path acts as the centripetal force. Since it is perpendicular to the direction of motion, always. Hence, the work done by this force is also zero work.

Learn more about zero work here:

https://brainly.com/question/21650213?referrer=searchResults

The attached picture shows examples of zero work.