How to Determine the Coefficient of Friction for a Block?

AI Thread Summary
The coefficient of friction is defined as the ratio of the frictional force (Ff) to the normal force (Fn), expressed as u = Ff/Fn. To determine the frictional force, one must either be given it or measure it, as it is not inherently known. The discussion highlights the need to clarify whether the friction is kinetic or static and whether the surface is horizontal, as these factors influence the calculation. The equation Ff = umg is mentioned, indicating that the normal force (Fn) is equal to mg on a horizontal surface. Understanding these variables is crucial for accurately determining the coefficient of friction for a block.
11thgradephysics
Messages
9
Reaction score
0
how do i find the coefficient of friction of a block?
is it Ff/Fn?
the problem is how do i find the friction force?
 
Physics news on Phys.org
What does the problem ask, the coefficient of friction of a block does not make sense. Its always between two surfaces.
 
11thgradephysics said:
how do i find the coefficient of friction of a block?
is it Ff/Fn?
the problem is how do i find the friction force?
If I'm interpreting your question correctly, then you want to know whether the coefficient of friction is the frictional force divided by the normal force, right? This has been true for my uses of it, but there's probably a better definition somewhere.
 
u = coefficient of friction
Ff = umg
u = Ff / mg
you need either one..
mg is also known as Fn
 
Be careful kaitamasaki, Fr isint equal to umg.
 
Not clear whether you are trying to find the friction force or the coefficient of friction. (You've got to be given--or measure--something.) Also: Is the friction kinetic or static? Is the surface horizontal?
 

Thread 'Errors and significant figures'

I multiplied the values first without the error limit. Got 19.38. rounded it off to 2 significant figures since the given data has 2 significant figures. So = 19. For error I used the above formula. It comes out about 1.48. Now my question is. Should I write the answer as 19±1.5 (rounding 1.48 to 2 significant figures) OR should I write it as 19±1. So in short, should the error have same number of significant figures as the mean value or should it have the same number of decimal places as...
View full post »
Thread 'A cylinder connected to a hanging mass'

Thread 'A cylinder connected to a hanging mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
View full post »

Similar threads

Friction Coefficients: Determining Force Direction?
Replies
6
Views
1K
Yes! Calculating Friction Coefficient
Replies
1
Views
1K
Angular velocity- A toy train rolls around a horizontal track
Replies
8
Views
750
Friction problem of a block sandwiched between 2 surfaces
Replies
6
Views
1K
Mechanical Physics: Coefficient of Friction
Replies
20
Views
3K
Coefficient of Friction question for a cart going down a wooden ramp
Replies
18
Views
3K
Coefficient of Friction when Normal Force is Reduced [HS]
Replies
5
Views
2K
Finding the work done by a block
Replies
4
Views
3K
Investigation regarding the rotor ride
Replies
8
Views
889
Find the force of Friction and minimum coefficient of friction
Replies
1
Views
2K

Hot Threads

Recent Insights

Back
Top