Question about frictional and normal force

AI Thread Summary
To determine the frictional force acting on a stationary wall with a mass of 150 kg and a coefficient of friction of 2, it's essential to first identify the normal force. The frictional force formula, Fr = (mu)(Fn), indicates that friction depends on the normal force applied. If the wall does not move, the static frictional force is only as large as necessary to prevent motion, meaning it can be zero if no other forces are acting in that direction. The correct interpretation of the equation is |Fr| <= mu |Fn|, emphasizing that frictional force is contingent on the normal force. Understanding these principles is crucial for solving the problem accurately.
imagesparkle
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Homework Statement


Okay so there is a wall that has a mass of 150 kg and I am pushing it but the wall does not move. The coefficient of friction is 2 and I am trying to find the frictional force using the frictional force formula. Although, I need the normal force in which I am using to push the wall but don't know how to find the normal force.

Homework Equations


Fr = (mu)(Fn)

The Attempt at a Solution

 
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imagesparkle said:

Homework Statement


Okay so there is a wall that has a mass of 150 kg and I am pushing it but the wall does not move. The coefficient of friction is 2 and I am trying to find the frictional force using the frictional force formula. Although, I need the normal force in which I am using to push the wall but don't know how to find the normal force.

Homework Equations


Fr = (mu)(Fn)

The Attempt at a Solution

You need to describe the set up better. Frictional force between what two objects - you and the wall?
Friction acts parallel to the surfaces in contact. If there is no movement and no other forces in that direction then the frictional force will be zero, regardless of the coefficient. The static frictional force is only as large as it needs to be to prevent relative motion. The correct equation is |Fr| <= mu |Fn|.
 

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