NaBrO
Badges: 12
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#1
Report Thread starter 1 year ago
#1
Does friction increase closer to a particle stopping?
E.g. if a particle has driving force 10N and friction 5N, when it stops, will friction be 15N (5 + 10)? Or, is the friction force related to the speed at which it stops?
0
reply
JGLM
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#2
Report 1 year ago
#2
Frictional force is not dependent on the speed of the object.
The force is proportional to the contact force between the object and surface, and the friction coefficient (a measure of roughness between the two).
When moving, the friction force is always equal to the product of the two. When not moving, the friction is always less than the product of the two.
F=mR (moving)
F<mR (not moving)
The friction coefficient is a constant unique to the two things in contact.
1
reply
Stonebridge
Badges: 13
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#3
Report 1 year ago
#3
(Original post by NaBrO)
Does friction increase closer to a particle stopping?
E.g. if a particle has driving force 10N and friction 5N, when it stops, will friction be 15N (5 + 10)? Or, is the friction force related to the speed at which it stops?
If the frictional force is 5N and the driving force 10N then the object does not stop. It has a resultant force of 10-5 N so it keeps going.

There is also what is called 'static' friction and 'dynamic' friction.
Between 2 objects, the static friction, when there is no movement, is slightly greater than the dynamic friction when they are sliding over each other.
This might be what you are thinking of.
0
reply
JGLM
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#4
Report 1 year ago
#4
(Original post by Stonebridge)
If the frictional force is 5N and the driving force 10N then the object does not stop. It has a resultant force of 10-5 N so it keeps going.

There is also what is called 'static' friction and 'dynamic' friction.
Between 2 objects, the static friction, when there is no movement, is slightly greater than the dynamic friction when they are sliding over each other.
This might be what you are thinking of.
Other way round
0
reply
Stonebridge
Badges: 13
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#5
Report 1 year ago
#5
(Original post by JGLM)
Other way round
I assume you mean the OP as got it the wrong way round.
In the case when the friction is 10N and driving force 5N, the object does indeed stop.
At that point the object remains at rest with the driving force still 5N and being opposed by a frictional force of 5N.
Zero resultant. No further motion.
The frictional force cannot be greater that the applied force.
Last edited by Stonebridge; 1 year ago
0
reply
JGLM
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#6
Report 1 year ago
#6
(Original post by Stonebridge)
I assume you mean the OP as got it the wrong way round.
In the case when the friction is 10N and driving force 5N, the object does indeed stop.
At that point the object remains at rest with the driving force still 5N and being opposed by a frictional force of 5N.
Zero resultant. No further motion.
The frictional force cannot be greater that the applied force.
It can be if it’s moving (and decelerating). I meant that the static friction is always less than (or equal to in limiting equilibrium) the dynamic friction.
0
reply
Stonebridge
Badges: 13
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#7
Report 1 year ago
#7
(Original post by JGLM)
It can be if it’s moving (and decelerating). I meant that the static friction is always less than (or equal to in limiting equilibrium) the dynamic friction.
Indeed. The OP was, though, asking about the case where the object has stopped. Then in that case the frictional force cannot be greater than the applied force, and the applied force needs to be greater than the static frictional force to get it moving again.
I think we've answered the question now.
0
reply
JGLM
Badges: 15
Rep:
? You'll earn badges for being active around the site. Rep gems come when your posts are rated by other community members.
#8
Report 1 year ago
#8
(Original post by Stonebridge)
Indeed. The OP was, though, asking about the case where the object has stopped. Then in that case the frictional force cannot be greater than the applied force, and the applied force needs to be greater than the static frictional force to get it moving again.
I think we've answered the question now.
Ahh yes I misinterpreted what you said. Relative to the parallel force, yeah. Lol
0
reply
X

Quick Reply

Attached files
Write a reply...
Reply
new posts
Back
to top
Latest

Were exams easier or harder than you expected?

Easier (41)
26.8%
As I expected (49)
32.03%
Harder (56)
36.6%
Something else (tell us in the thread) (7)
4.58%

Watched Threads

View All