Rotational motion, frictionless.

  • Thread starter azizlwl
  • Start date
  • #1
1,065
10
http://img444.imageshack.us/img444/8148/rollwx.jpg [Broken]

A rope is wound around a cylinder of mass 4kg, and I=0.02kg.m2 about the cylinder axis.
The frictional force between table and cylinder is negligible.

Solution:
a=20/4=5.0m/s2
α=ar is not applicable when slippage occurs.


My question.
1.Is the cylinder moves forward with acceleration a without any rotation.
2. Is Fr=Iα is still applicable in this case, even though we know α=ar not applicable.
3. If we play yo-yo in zero gravity environment,how does the yo-yo behave when we pull it?

Thank you.
 
Last edited by a moderator:

Answers and Replies

  • #2
K^2
Science Advisor
2,469
29
1. No, see 2.
2. Yes, Fr=Iα is always applicable. α=ar constraint is only needed for rolling, and is achieved via additional force, that being the force of friction. When no friction is present, you just compute angular and linear accelerations separately.
3. Yo-yo in zero-g will behave exactly the same as this test case. It will accelerate and spin in direction it's being pulled.
 
  • #3
1,065
10
Thank you.
That really helpful since the book didn't say about rotation only a=αr is not applicable.
 
  • #4
haruspex
Science Advisor
Homework Helper
Insights Author
Gold Member
34,575
5,978
A nice question to ask here is to find the instantaneous centre of rotation.
 

Related Threads on Rotational motion, frictionless.

Replies
1
Views
537
Replies
23
Views
1K
  • Last Post
2
Replies
29
Views
7K
  • Last Post
Replies
3
Views
2K
Replies
9
Views
1K
Replies
3
Views
3K
  • Last Post
Replies
3
Views
3K
Replies
21
Views
9K
Replies
2
Views
4K
Top