Finding the force on a cord from a pulley

In summary, the student is trying to find the 'String R (lower part)' force. They are asking for help with this question, and have tried to do some calculations themselves. It is difficult to tell where they are having trouble, so they ask for help. If it is not homework, the student would like to see a free body diagram of the pulley.
  • #1
Johno123
3
0
(Mentor note: moved from General Eng hence not homework template)

upload_2018-8-31_16-3-6.png


This is the given scenario. I'm trying to find the 'String R (lower part)' force. I know every other variable (the angles, string L and string R and the Rectangle is a mass m). Any help would be appreciated!
 

Attachments

  • upload_2018-8-31_16-3-6.png
    upload_2018-8-31_16-3-6.png
    5.4 KB · Views: 848
Last edited by a moderator:
Physics news on Phys.org
  • #2
Is that a mass m hanging from String R?
 
  • Like
Likes CWatters and Johno123
  • #3
256bits said:
Is that a mass m hanging from String R?

Yes sorry I forgot to put that in! Just fixed it.
 
  • #4
Johno123 said:
Yes sorry I forgot to put that in! Just fixed it.
Hi again.
If this is homework, we have a section called Homework Help, to which it can be moved.
Is it homework?

It has an outline to follow, which gives you a much better responses from people who will guide you to a solution.
 
  • #5
256bits said:
Hi again.
If this is homework, we have a section called Homework Help, to which it can be moved.
Is it homework?

It has an outline to follow, which gives you a much better responses from people who will guide you to a solution.

No its not homework. I'm doing some study ahead for my course next year and I wanted some help with this question.
 
  • #6
Johno123 said:
No its not homework. I'm doing some study ahead for my course next year and I wanted some help with this question.
So what have you tried so far?
It is difficult to tell where you are having trouble without showing some of your calculations and equations.
 
  • #7
Johno123 said:
I'm trying to find the 'String R (lower part)' force.
That's confusing to me.
It looks like a trivial question because string R's lower segment just holds up mass M.
Yet you titled your thread :
"force on a cord from a pulley"

If nothing is in motion that seems straightforward to find.

Have you drawn a free body diagram of that pulley showing the forces on it? Since nothing is moving you can make believe everything is glued together.
 
  • #8
256bits said:
Is that a mass m hanging from String R?
That was probably a hint rather than a question.
 
  • Like
Likes scottdave
  • #9
It like be interesting to see the whole problem statement.
 
  • #10
Do you know how the tension in string R in the upper part compares with the lower part? If you are studying ahead, this is an important part of your learning.
 
  • Like
Likes jim hardy

FAQ: Finding the force on a cord from a pulley

What is a pulley?

A pulley is a simple machine that consists of a wheel with a groove around its circumference and a rope or cord that runs through the groove. It is used to change the direction of force and to lift heavy objects.

How does a pulley work?

A pulley works by changing the direction of the force applied to an object. When a force is applied to one end of the rope, the pulley redirects the force to the other end, allowing for easier lifting or moving of heavy objects.

How do you find the force on a cord from a pulley?

To find the force on a cord from a pulley, you must consider the number of ropes supporting the load and the direction of the force applied. The force on the cord is equal to the weight of the load divided by the number of supporting ropes.

What is the relationship between the number of ropes supporting the load and the force on the cord?

The more ropes supporting the load, the less force is required on the cord to lift the load. This is because the weight of the load is distributed among the ropes, reducing the force required on each individual rope.

Are there different types of pulleys?

Yes, there are three types of pulleys: fixed, movable, and compound. Fixed pulleys are attached to a stationary object and do not move. Movable pulleys are attached to the object being lifted and move with it. Compound pulleys combine fixed and movable pulleys to provide a mechanical advantage, making it easier to lift heavy loads.

Back
Top