Rotational Motion on an Inclined Plane

[UMich1344]

What force does work on a ball as it is rotating down an inclined plane? Explain why the other forces the ball experiences do not do work.

I think the ball experiences gravitational, normal, and frictional forces. Is the force that actually does work on the ball just gravity? I'm having a hard time understanding this concept. Friction is what is causing the rotation, since on a frictionless inclined plane the ball would just slide down. But I don't know how to explain why a given force does or does not do work on the ball.

 

[rock.freak667]

Start with the definition of work.

Work is done when a force moves its point of application in the direction of motion.

With the normal force, is the force and motion in the same direction?

 

[Sniperman724]

I think the frictional force is one of the forces that does work on the ball, I am not quite sure about the other forces

 

[rock.freak667]

I think the frictional force is one of the forces that does work on the ball, I am not quite sure about the other forces

Well on the ball, there is the force down the slope, friction and the normal force.

You are correct that the frictional force does work, would the force down the slope do work?

Remember to see if the force is in the same direction in which the ball is moving.

 

[rwisz]

As the ball is rotating down an inclined plane, the force that does work on it is primarily gravity. This is because gravity is the force that is responsible for the ball's downward motion and is the force that is causing the ball to move. The other forces, such as normal and frictional forces, do not do work on the ball because they are acting perpendicular or parallel to the direction of motion, respectively.

The normal force is the force that is exerted on the ball by the inclined plane in order to prevent it from sinking into the surface. This force is acting at a right angle to the direction of motion, so it does not contribute to the work done on the ball.

Similarly, the frictional force is acting parallel to the surface of the inclined plane, which means it is not contributing to the work done on the ball. Friction is what allows the ball to rotate as it slides down the inclined plane, but it is not the force that is causing the ball to move.

In order for a force to do work on an object, it must be applied in the direction of motion. This is why gravity is the only force that does work on the ball as it rotates down the inclined plane. It is important to note that while friction may be necessary for the ball to rotate, it is not doing any work on the ball itself.

In summary, the force that does work on a ball as it rotates down an inclined plane is primarily gravity. The other forces, such as normal and frictional forces, do not do work because they are not acting in the direction of motion.