Calculating coefficient of max static friction

AI Thread Summary
The discussion focuses on calculating the coefficient of max static friction, emphasizing the relationship between contact force, surface quality, and friction. It confirms that the maximum static force increases with heavier weights. To calculate the normal force, it is clarified that it equals the mass of the weight multiplied by gravity (9.81 m/s²) on a level surface. For inclined surfaces, the normal force is reduced and calculated using the cosine of the angle of inclination. Understanding these principles is essential for accurate friction analysis in experiments.
arjfsdsr
Messages
1
Reaction score
0
Hello,

I'm conducting an experiment about how contact force and surface quality affect friction. I know that friction is affected by both, as my data suggests. I measured the static forces of several weights on two different surfaces, and found that indeed the max static force increased as the weights got heavier.

For analysis, I'd like to calculate the coefficients of the max static forces, and I know this is equal to (max static force / normal force), but I'm wondering how to calculate the normal forces of each weight. Is it just equal to the mass of each weight times gravity??

Thanks so much!
 
Physics news on Phys.org
arjfsdsr said:
Is it just equal to the mass of each weight times gravity??

Yep, consider force balance in the vertical direction.
 
arjfsdsr said:
Is it just equal to the mass of each weight times gravity??
Yes, mass in Kg times gravity (9.81 m/s^2) will give you the force of gravity (in Newtons) that is pulling the object toward the center of the Earth.

If the object is on a level surface, than the force of gravity equal in magnitude to the normal force.

But, if the object is on a slant with an angle "theta" from horizontal, the normal force is the gravitational force times the cosine of "theta". The normal force in this case will be less than it would be on a level surface.
 

Attachments

  • normal.jpg
    normal.jpg
    9.3 KB · Views: 513
Hi there, im studying nanoscience at the university in Basel. Today I looked at the topic of intertial and non-inertial reference frames and the existence of fictitious forces. I understand that you call forces real in physics if they appear in interplay. Meaning that a force is real when there is the "actio" partner to the "reactio" partner. If this condition is not satisfied the force is not real. I also understand that if you specifically look at non-inertial reference frames you can...
This has been discussed many times on PF, and will likely come up again, so the video might come handy. Previous threads: https://www.physicsforums.com/threads/is-a-treadmill-incline-just-a-marketing-gimmick.937725/ https://www.physicsforums.com/threads/work-done-running-on-an-inclined-treadmill.927825/ https://www.physicsforums.com/threads/how-do-we-calculate-the-energy-we-used-to-do-something.1052162/
I have recently been really interested in the derivation of Hamiltons Principle. On my research I found that with the term ##m \cdot \frac{d}{dt} (\frac{dr}{dt} \cdot \delta r) = 0## (1) one may derivate ##\delta \int (T - V) dt = 0## (2). The derivation itself I understood quiet good, but what I don't understand is where the equation (1) came from, because in my research it was just given and not derived from anywhere. Does anybody know where (1) comes from or why from it the...
Back
Top