Force and friction

  • #1
We know that force * coeff. of friction = m * g. . It does not make sense. Pls read details. This is when force is applied perpendicular to the direction of friction. But suppose we say that m = 10 kg, g = 10 m/s2, coeff. of friction is 0.1. Then by formula it says that force required to keep the object against the wall will be 1000 N. How does this make sense? I mean the force required to lift the object without any support is just m*g = 100 N. Pls explain this so that it makes intuitive sense......
 

Answers and Replies

  • #2
Simon Bridge
Science Advisor
Homework Helper
17,874
1,657
We know that force * coeff. of friction = m * g. . It does not make sense.
Of course it doesn't, it is nonsense.

This is not correct ... the usual equation is ##F=\mu N## where "N" is the magnitude of the contact force between the surfaces.
Where that is a horizontal flat surface, ##N=mg## ... which is to say it's the weight of the object.

Pls read details. This is when force is applied perpendicular to the direction of friction. But suppose we say that m = 10 kg, g = 10 m/s2, coeff. of friction is 0.1. Then by formula it says that force required to keep the object against the wall will be 1000 N. How does this make sense?
Oh you mean that you are applying the normal force?

If you want friction to hold a box against it's weight, on a wall that slippery, then sure ... you will need a lot of force... especially if you are only applying the force horizontally.

Please see:
http://hyperphysics.phy-astr.gsu.edu/hbase/frict.html
http://www.engineeringtoolbox.com/friction-coefficients-d_778.html
 
Last edited:

Related Threads on Force and friction

  • Last Post
Replies
2
Views
747
  • Last Post
Replies
7
Views
3K
Replies
3
Views
859
  • Last Post
Replies
1
Views
4K
  • Last Post
Replies
13
Views
883
  • Last Post
Replies
2
Views
2K
  • Last Post
Replies
2
Views
1K
  • Last Post
Replies
8
Views
6K
  • Last Post
Replies
8
Views
577
  • Last Post
Replies
16
Views
1K
Top