Force tension, friction, and coefficient of friction

In summary, the conversation is discussing a problem where a child is pulling a friend on a sled with a constant tension of 29.4 N in the rope. The combined mass of the friend and sled is 30.0 kg, and the coefficient of sliding friction between the sled and snow is 0.1. The question is how far the child can pull her friend in 6 seconds. The conversation includes attempts at finding the net force and acceleration, but there seems to be some missing information in the problem statement.
  • #1
katie beisel
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0

Homework Statement


A child pulls a friend on a sled. The child maintains a constant tension of 29.4 N in the rope. The combined mass of the friend and sled is 30.0 kg, and the coefficient of sliding friction between the sled and snow is 0.1. How far can the child pull her friend in 6 sec?

Homework Equations


F = ma
fk = muk x FN
Ff = mu x FN
Fw/2 = FT

The Attempt at a Solution


so I got the force weight of the child and the sled is 294 N
so the force normal of the child and sled is 294N
fk = 0.1 x 294 = 29.4
and the force tension is 29.4 so 29.4 = Fw/2
= 58.8 N = Fw but i don't know what weight that is
and i need another equation to put this in but i don't know which one
 
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  • #2
Can we assume that the rope is being pulled horizontally?
katie beisel said:
Fw/2 = FT
I don't recognize that equation. Can you explain what it means?

katie beisel said:
so I got the force weight of the child and the sled is 294 N
so the force normal of the child and sled is 294N
fk = 0.1 x 294 = 29.4

Good. That's the force of friction.

So what's the net force on the sled+friend?

(I think there is key information missing from this problem statement. Is it from a textbook?)
 
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  • #3
Doc Al said:
(I think there is key information missing from this problem statement. Is it from a textbook?)
Probably can assume it means from rest.
 
  • #4
What does Fw/2=Ft mean?
I believe you need to work out the resultant force on the sled. After finding the resultant force, use Newton Second law of motion, F=ma to find the acceleration,a
After that, you can apply formula for motion in constant acceleration. since u are assuming the sled is at rest, use the information that u have and substitute it to a suitable formula(there are 4 formulae for motion in constant acceleration) a,u,t and you can find the displacement
 
  • #5
Doc Al said:
Can we assume that the rope is being pulled horizontally?

I don't recognize that equation. Can you explain what it means?
Good. That's the force of friction.

So what's the net force on the sled+friend?

(I think there is key information missing from this problem statement. Is it from a textbook?)
I'm actually not sure what the equation is, my teach wrote it on the board and i wrote it down, maybe it was just for a specific problem, I'm not sure.
well on the sled and friend there's the 29.4 N of friction pulling it back then the 29.4 N of FT, but wouldn't those cancel each other out? or is there something else?
 
  • #6
katie beisel said:
well on the sled and friend there's the 29.4 N of friction pulling it back then the 29.4 N of FT, but wouldn't those cancel each other out?
Yes, they would give a net force of zero and thus no acceleration. So the problem seems to be a bit off. Is this a textbook problem? Or something your instructor made up?
 

Related to Force tension, friction, and coefficient of friction

What is force tension?

Force tension is the pulling force that is generated when an object is stretched or pulled apart. It is always directed along the length of the object and can be caused by a variety of factors, such as weight, gravity, or a person pulling on the object.

What is friction?

Friction is the resistance force that occurs when two surfaces come into contact with each other. It can be caused by the roughness of the surfaces or the presence of microscopic bumps and ridges. Friction helps to slow down or stop the motion of objects.

What is the coefficient of friction?

The coefficient of friction is a dimensionless number that represents the amount of friction between two surfaces. It is a ratio of the force required to move an object over a surface to the weight of the object. It varies depending on the materials of the surfaces in contact and can range from 0 (no friction) to 1 (high friction).

How is friction related to the coefficient of friction?

The coefficient of friction is directly related to the amount of friction between two surfaces. A higher coefficient of friction means that there is more resistance to motion, while a lower coefficient of friction means there is less resistance. The coefficient of friction can also be affected by factors such as surface roughness, temperature, and pressure.

How does force tension affect friction?

Force tension can affect friction in a few ways. Firstly, it can increase the normal force between two surfaces, which in turn increases the friction force. Additionally, force tension can also change the angle at which two surfaces are in contact, thereby altering the amount of friction between them. Lastly, force tension can also cause objects to deform, which can increase or decrease the friction between two surfaces depending on the materials involved.

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