You are Here: Home >< Maths

# Circular Motion

Announcements Posted on
TSR's new app is coming! Sign up here to try it first >> 17-10-2016
1. Please could someone look over my working, I made a mistake somewhere in Q13.
Attached Images

2. (Original post by pippabethan)
Please could someone look over my working, I made a mistake somewhere in Q13.
I can't clearly follow what you're doing, as you seem to have used v for the velocity at the top and for the velocity at the bottom. If you're going to use the same letter, then you need to use a suffix to distinguish which is which.

Note also that is not the tension in the string when the ring is at the bottom. It is the radial component of the tensions in the string, which is hanging in a plane perpendicular to that of the ring's motion.

Also, . The whole thing is rather confusing. Your t's and E's are difficult to distinguish between as well.
3. Is this working easier to follow..
Attached Images

4. (Original post by pippabethan)
Is this working easier to follow..
Yep - a vast improvement.

In your diagram, you only have half the picture. The ring is hanging in the middle of the string, so there will be half the string on one side of the ring, and half on the other, and so two lots of tension supporting the ring.

Your next line talking about max tension occurs when radius is a max doesn't make sense to me. Radius doesn't change. Sin theta is going to be 4/5. I suspect your interpretation of the setup is causing the problem.

Here's my attempt at a diagram.
5. (Original post by ghostwalker)
Yep - a vast improvement.

In your diagram, you only have half the picture. The ring is hanging in the middle of the string, so there will be half the string on one side of the ring, and half on the other, and so two lots of tension supporting the ring.

Your next line talking about max tension occurs when radius is a max doesn't make sense to me. Radius doesn't change. Sin theta is going to be 4/5. I suspect your interpretation of the setup is causing the problem.

Here's my attempt at a diagram.
Aha, you're right, I misinterpreted the setup. I've got it now

## Register

Thanks for posting! You just need to create an account in order to submit the post
1. this can't be left blank
2. this can't be left blank
3. this can't be left blank

6 characters or longer with both numbers and letters is safer

4. this can't be left empty
1. Oops, you need to agree to our Ts&Cs to register

Updated: May 11, 2016
TSR Support Team

We have a brilliant team of more than 60 Support Team members looking after discussions on The Student Room, helping to make it a fun, safe and useful place to hang out.

This forum is supported by:
Today on TSR

### How does exam reform affect you?

From GCSE to A level, it's all changing

Poll
Useful resources

### Maths Forum posting guidelines

Not sure where to post? Read here first

### How to use LaTex

Writing equations the easy way

### Study habits of A* students

Top tips from students who have already aced their exams