find the point of rotation


by phys_learner
Tags: point, rotation
phys_learner
phys_learner is offline
#1
Apr8-09, 08:18 PM
P: 10
1. The problem statement, all variables and given/known data
A thin uniform plank of length L lies at rest on a horizontal sheet of ice. If the plank is given a kick at one end in a direction normal to the plank, show that the plank will begin to rotate about a point located L/6 from the center.


2. Relevant equations
The friction can be neglected.


3. The attempt at a solution Since the plank is free to move it has both rotational and translational motion after it gets the kick. If the centre of mass of the plank moves with linear velocity 'v', then its linear momentum is 'mv' where m is mass of plank, and angular momentum is mvr where 'r' is the distance from the CM. I tried conservation of momentum but(0=mv+ mvr) that did not lead to any result. Please shed some light on the problem. Thanking you in advance
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
1. The problem statement, all variables and given/known data



2. Relevant equations



3. The attempt at a solution
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Thaakisfox
Thaakisfox is offline
#2
Apr9-09, 02:04 AM
P: 263
You Cant mix the two quantities together. There is angular momentum and linear momentum ;) and you have energy too ;) ;)
phys_learner
phys_learner is offline
#3
Apr10-09, 12:25 AM
P: 10
I still cant figure out the correct way to solve this question. please more help required!!


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