Why Does Increasing Friction Not Lift an Object Against Gravity?

[AlbertE97]

The harder I push a book to a wall, the larger is the friction force, since friction is (coefficient of friction (times) the force I use).

Why won't the friction force make the object go up instead of stay where it is since the friction worse can get arbitrarily large while gravitational force is constant?

(not a homework question but one I thought of)(English is my 2nd language)

 

[jack action]

Friction is a reactive force, so you need another force to create the friction. In your case, the force is the weight of the book so the friction force will never be greater than the weight of the book.

What the coefficient of friction times the normal force equation tells you is the MAXIMUM force that friction can handle. So by pushing harder you do not increase friction, but if you would add another force pushing the book down (say adding weight on it), the friction force could still resists the increased downward force.

 

[Dr.D]

It is not clear in your original statement which direction you are pushing the book (parallel to the wall or perpendicular to the wall?).

What Jack said was very good.

 

[AlbertE97]

(parallel to the wall or perpendicular to the wall?)

Perpendicular.

 

[HalfLostAndSearching]

The friction force is a result of the interaction between two surfaces and is always in the opposite direction of the applied force. This means that the book will not go up because the friction force is acting in the opposite direction of the force you are using to push the book towards the wall. Additionally, the friction force can only increase to a certain point before it reaches its maximum value, known as the coefficient of friction. Beyond this point, the object will either start to slide or remain stationary, depending on the direction and magnitude of the applied force. On the other hand, the gravitational force is a constant force that acts in a downward direction, and it does not depend on the force you are using to push the book towards the wall. Therefore, the friction force will not make the object go up because it is always acting in the opposite direction of the applied force and can only increase to a certain point.