Why Is Work Equal to Zero When Forces Are Perpendicular?

[xtrubambinoxpr]

Homework Statement

See the picture attached please. I need help understanding the concept of why work is = 0. I don't understand it's explanation. Please bare with me for the silly questions.

Homework Equations

W=Kf-Ki

W=Fdcosθ

The Attempt at a Solution

I can't understand why It mentions the normal force acting perpendicular if its being pushed to the left not up.

 

[Doc Al]

See the picture attached please. I need help understanding the concept of why work is = 0.

The total work is zero, since the kinetic energy doesn't change. Look up the work-energy theorem.

I can't understand why It mentions the normal force acting perpendicular if its being pushed to the left not up.

The object is moving parallel to the the ramp, but the normal force acts perpendicular to it. So does the normal force do any work in this case?

 

[xtrubambinoxpr]

The total work is zero, since the kinetic energy doesn't change. Look up the work-energy theorem.


The object is moving parallel to the the ramp, but the normal force acts perpendicular to it. So does the normal force do any work in this case?

You will have to dumb it down a good amount for me =/

 

[1ndranil]

I can't understand why It mentions the normal force acting perpendicular if its being pushed to the left not up.

If a particle moves on a frictionless rigid surface, due to the fact that this surface constrains the motion of the particle, we have an additional force acting (locally) perpendicularly to the surface.