Why Does Increasing Friction Not Lift an Object Against Gravity?

AI Thread Summary
Increasing friction does not lift an object against gravity because friction is a reactive force that depends on the normal force, which in this case is the weight of the object. The friction force can only reach a maximum equal to the weight of the object, meaning it cannot exceed this limit regardless of how hard one pushes. Adding weight to the object can increase the friction force, allowing it to resist greater downward forces. The direction of the applied force also matters; in this case, pushing perpendicular to the wall does not contribute to lifting the object. Thus, friction alone cannot overcome gravitational force to lift the object.
AlbertE97
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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)
 
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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.
 
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.
 
Dr.D said:
(parallel to the wall or perpendicular to the wall?)

Perpendicular.
 
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