What is the static friction force acting on the object?

In summary, the coefficient of static friction for a block on a flat surface is 0.5 and the normal force acting on the block is 10N. When someone applies a horizontal force of 2N, the maximum possible force of static friction is 5N. However, the correct answer is 2N, as the frictional force cannot exceed the applied force when the object is at rest. This is due to the "less than or equal to" rider in the equation fs=usR.
  • #1
unknown physicist
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Homework Statement


A block sitting on a flat surface has a us of 0.5. The normal force acting on the block is 10N. If someone pushes the block with a horizontal force of 2N. What is the static friction force acting on the object?

Homework Equations


F=ma
fs=usR (less than or equal to)

The Attempt at a Solution


I said that since the coefficient of static friction is 0.5, therefore if we multiply it by 10N then we will get 5N, and that is force of static friction. However the answer is incorrect and the correct answer is 2N. Why is that? Isn't 2N the applied force?
 
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  • #2
unknown physicist said:
therefore if we multiply it by 10N then we will get 5N, and that is force of static friction
It is the "maximum" possible force of static friction.
Also, how can the frictional force be more than the applied force when the object is at rest?
 
  • #3
unknown physicist said:
fs=usR (less than or equal to)
Did you not understand the significance of the "less than or equal to" rider?
 

FAQ: What is the static friction force acting on the object?

1. What is static friction?

Static friction is a force that prevents two surfaces from sliding against each other when they are in contact and at rest.

2. How is static friction different from kinetic friction?

Static friction acts on objects that are not moving, while kinetic friction acts on objects that are in motion.

3. What factors affect the magnitude of the static friction force?

The magnitude of the static friction force depends on the nature of the two surfaces in contact, the normal force applied, and any other external forces acting on the object.

4. Can the static friction force be greater than the weight of an object?

Yes, the static friction force can be greater than the weight of an object if the applied force is large enough to overcome the friction force.

5. How is the static friction force calculated?

The static friction force can be calculated using the formula Fs = μsN, where μs is the coefficient of static friction and N is the normal force between the two surfaces.

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