Coefficient of static friction experiment

In summary, the angle at which an object will start moving is independent of mass. This can be proved using the formula for acceleration, which shows that mass does not affect the angle. The frictional force is also independent of mass and is equal to μsN, where N is the normal force. The object will start to move when the force down the slope is equal to the maximum friction force, which can be seen by setting the force equal to the maximum friction force. Therefore, μs = sinpheta/cospheta, which shows that μs is independent of mass. The Galileo experiment with gravity shows that the rate of fall of an object is likewise independent of mass, but this is not applicable to the current problem of
  • #1
physicshelpppp
9
0
1. Problem

I am currently doing a home experiment about the coefficient of static friction. I've set up a ramp and am testing at which angle a tissue box begins to movie (with five different masses in it)... Although for every mass I use the angle seems to remain the same. The angle at which an object will start moving is independent of mass right? Mass is important when there is no friction?
 
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  • #2
The angle at which an object will start moving is independent of mass right?

Have you covered the maths at school yet? If you have then try proving it that way.
 
  • #3
The acceleration is given by a factor of $$ g*(sin(Θ) - μcos(Θ) )$$
yes..it doesn't thepend from mass
 
  • #4
I have been looking at questions, when I do a worked question...

and the force down (weight force) on the object would be mgsinpheta and the force perpendicular is mgcospheta
which has same magnitude as normal force

so frictional force is = μsN (where is normal force is equal to perpendicular force)

therefore Ffr = μsmgcospheta
the object will start to move when the force down the slope is equal to the maximum friction force

therefore

mgsinpheta = μsmgcospheta

(therefore we can cancel the mg out on both sides)

and then we are left with μs = sinpheta/cospheta therefore μs = tanphetatherefore it is independent of mass?
 
  • #5
Correct. Nice to see theory and experiment agree.
 
  • #6
physicshelpppp said:
I have been looking at questions, when I do a worked question...

and the force down (weight force) on the object would be mgsinpheta and the force perpendicular is mgcospheta
which has same magnitude as normal force

so frictional force is = μsN (where is normal force is equal to perpendicular force)

therefore Ffr = μsmgcospheta
the object will start to move when the force down the slope is equal to the maximum friction force

therefore

mgsinpheta = μsmgcospheta

(therefore we can cancel the mg out on both sides)

and then we are left with μs = sinpheta/cospheta therefore μs = tanpheta


therefore it is independent of mass?
it isn't...remember the galileo experiment with gravity :)
 
  • #7
Domenico94 said:
it isn't...remember the galileo experiment with gravity :)
The galileo experiment shows that the rate of fall of an object is likewise independent of mass. But that is not what is involved in the present static friction problem under investigation.

Chet
 

What is the coefficient of static friction?

The coefficient of static friction is a measure of the amount of force required to overcome the static friction between two surfaces in contact with each other. It is a dimensionless quantity and is typically denoted by the symbol μ (mu).

Why is it important to measure the coefficient of static friction?

The coefficient of static friction is important because it helps us understand the amount of force required to keep an object at rest on a surface. This information is crucial in engineering and design to ensure that objects do not slip or move unintentionally.

How is the coefficient of static friction experiment performed?

The coefficient of static friction experiment involves placing an object on a surface and gradually increasing the force applied to the object until it begins to move. The force required to move the object is then divided by the weight of the object to determine the coefficient of static friction.

What factors can affect the coefficient of static friction?

The coefficient of static friction can be affected by several factors, including the roughness of the surface, the weight of the object, and the materials of the two surfaces in contact. It can also be affected by external factors such as temperature and humidity.

How is the coefficient of static friction used in real-world applications?

The coefficient of static friction is used in many real-world applications, such as designing tires for vehicles, determining the stability of structures, and calculating the force required to move objects on different surfaces. It is also important in sports, where the right amount of friction is necessary for proper performance.

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