A rope hanging over edge of table.

In summary: It is against our rules and can lead to confusion for other users.In summary, the conversation discusses an extra credit problem involving finding the fraction of a rope that can hang over the edge of a table before it begins to slip, using the coefficient of static friction between the rope and the table. The equation (0.3)(M-n[M/L])g=[n M/L]g is suggested, but it is noted that only gravity and the coefficient of friction are needed to solve the problem. Setting the force of friction equal to the force of gravity is recommended, and it is clarified that only the portion of the rope on the table will contribute to the force of friction.
  • #1
myaaxcore
9
0
The coefficient of statis friction between a rope and the table on which it rests is 0.3. Find the fraction of the rope that can hang over the edge of the table before it begins to slip.

This is an extra credit problem so we haven't learned this yet. I don't know where to start but I'm guessing that to find that fraction of the rope, you need the mass,the weight and the gravitational force and stuff??
cluless >.< please help.
 
Physics news on Phys.org
  • #2
Rope hanging over edge of table.

question
The coefficient of static friction between a rope and the table on which it rests is 0.3. Find the fraction of the rope that can hang over the edge of the table before it begins to slip.

Equation/ attempt at solution
well, i googled this question and the equation i came up with was
(0.3)(M-n[M/L])g=[n M/L]g .

But as this is an extra credit problem and we haven't learned this yet, I am not sure what I'm doing.
Clueless, please please help.
 
  • #3


Draw a diagram of the forces.
You have a weight pulling down on the hanging part, how will this weight depend on the length?
This is balanced by the friction on the table part, friction = 0.3 * downward force (ie the weight of the part still on the table)

If you think carefully the actual weight/metre of the rope doesn't matter, can you see why
 
  • #4
you don't need to now the length or mass of the rope to solve this. Only gravity and the coefficient of friction are needed.
To solve you need to set the force of friction equal to the force of gravity.
Keep in mind only the portion of the rope on the table will contribute to the force of friction and only the part off of the table will contribute to the force of gravity.
 
  • #5
Moderator's note: two threads merged into one.

Note to myaaxcore: please do not start multiple threads to ask the same question.
 

Related to A rope hanging over edge of table.

1. What is the force exerted by the rope hanging over the edge of a table?

The force exerted by the rope hanging over the edge of a table is the tension force. This force is created by the weight of the rope itself and any additional weight that is attached to it.

2. How does the length of the rope affect the tension force?

The longer the rope, the greater the tension force. This is because a longer rope means there is more weight pulling down on the rope, creating a larger tension force.

3. Does the mass of the object attached to the rope affect the tension force?

Yes, the mass of the object attached to the rope will affect the tension force. The greater the mass, the greater the weight pulling down on the rope and therefore, the greater the tension force.

4. What happens to the tension force if the angle of the rope changes?

If the angle of the rope changes, the tension force will also change. The tension force will decrease as the angle of the rope increases, and it will increase as the angle of the rope decreases.

5. Is the tension force the only force acting on the rope?

No, the tension force is not the only force acting on the rope. There may also be other forces, such as friction, acting on the rope depending on the specific scenario.

Similar threads

  • Introductory Physics Homework Help
Replies
4
Views
1K
  • Introductory Physics Homework Help
Replies
12
Views
4K
  • Introductory Physics Homework Help
Replies
4
Views
2K
  • Introductory Physics Homework Help
Replies
1
Views
2K
  • Introductory Physics Homework Help
Replies
5
Views
4K
  • Introductory Physics Homework Help
Replies
33
Views
2K
  • Introductory Physics Homework Help
Replies
4
Views
16K
  • Introductory Physics Homework Help
Replies
1
Views
5K
  • Introductory Physics Homework Help
Replies
3
Views
3K
  • Introductory Physics Homework Help
Replies
4
Views
2K
Back
Top