Help in Homework -- difference b/w kinematics friction and static friction?

  • #1
Hi,

Please explain what is the difference b/w kinematics friction and static friction ?

Please explain, what is rolling friction ?
Is it when we are pulling a weight with rope, and rope is rolling on a wheel ?
for example in past days, people used rope to get water from well.

Please explain it.

Thanks.
 

Answers and Replies

  • #2
berkeman
Mentor
58,009
8,070
Hi,

Please explain what is the difference b/w kinematics friction and static friction ?

Please explain, what is rolling friction ?
Is it when we are pulling a weight with rope, and rope is rolling on a wheel ?
for example in past days, people used rope to get water from well.

Please explain it.

Thanks.
What do you think the difference is between static friction and dynamic friction? What do you find when you use Wikipedia or Google?
 
  • Like
Likes *.*.*AnUm*.*.*
  • #3
I think static friction when any force causes friction
dynamic friction when a body is moving, right ?
 
  • #6
In other words,

  • static friction between non-moving surfaces, and kinetic friction between moving surfaces, right ?
 
  • #7
Is this explanation correct:

"Please explain, what is rolling friction ?
Is it when we are pulling a weight with rope, and rope is rolling on a wheel ?
for example in past days, people used rope to get water from well.
"
 
  • #8
berkeman
Mentor
58,009
8,070
In other words,

  • static friction between non-moving surfaces, and kinetic friction between moving surfaces, right ?
Yep!
 
  • Like
Likes *.*.*AnUm*.*.*
  • #9
berkeman
Mentor
58,009
8,070
Is this explanation correct:

"Please explain, what is rolling friction ?
Is it when we are pulling a weight with rope, and rope is rolling on a wheel ?
for example in past days, people used rope to get water from well.
"
I think of rolling friction more like between a tire and the road. But I suppose it would also apply to a rope over a pulley too.
 
  • Like
Likes *.*.*AnUm*.*.*
  • #11
And I think friction shouldn't be constant, is it correct ?
 
  • #12
haruspex
Science Advisor
Homework Helper
Insights Author
Gold Member
34,333
5,890
And I think friction shouldn't be constant, is it correct ?
Static friction can never be less than kinetic friction, but I know of no rule that says it has to be more.
In reality, friction is rather more complicated than is taught in school. But generally you are safe to say that each of the two coefficients of friction of a given combination of surfaces is constant, not varying according to normal force nor, in the case of kinetic friction, according to relative speed of the two surfaces.
 
  • #13
berkeman
Mentor
58,009
8,070
And I think friction shouldn't be constant, is it correct ?
The wikipedia article that I linked to earlier in this thread answers that question. :smile:
 

Related Threads on Help in Homework -- difference b/w kinematics friction and static friction?

  • Last Post
Replies
14
Views
2K
  • Last Post
Replies
3
Views
620
  • Last Post
Replies
2
Views
2K
Replies
4
Views
3K
Replies
1
Views
757
Replies
1
Views
3K
Replies
4
Views
2K
Replies
7
Views
4K
  • Last Post
Replies
3
Views
473
Top