Concept Question. Force and Work.

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SUMMARY

The discussion centers on whether the normal force can perform work on an object. It is established that if there is no displacement, the normal force does not do work. However, when the normal force acts between two objects in motion, such as during a push or a collision, it can indeed do work if it is not perpendicular to the direction of motion. The ambiguity of the term "normal force" is highlighted, suggesting that context is crucial for accurate interpretation.

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  • Familiarity with the work-energy principle
  • Knowledge of normal force in mechanics
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Homework Statement



Can the normal force on an object ever do work?

Homework Equations



Work= Force x displacement


The Attempt at a Solution



My guess would be no (if there is not any displacement.)
 
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Your guess is correct. If there no displacement there is no work.
 
If by "normal" force is meant normal to the direction of the motion then the work is zero by definition.

However "normal force" can mean the force normal to the contact surface between two objects. When you push an object with another one, the first one is acted upon by the normal force acting between the two objects and it moves along its direction. Work is done in this case. The normal force is not normal to the direction of motion.
The same thing is true for a collision. The interaction forces between the colliding objects have a normal component (may have a tangential component for non centric collision) that does work.

I think is an ambiguous question, out of context. Maybe in the context of the chapter in the textbook with the problem, the meaning was well defined.
 

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