# Find the minimum velocity for bucket in circular motion

1. Mar 27, 2012

### Tui

Hey, first of all I'm not looking for the answer I just want a nudge in the right direction :)

1. The problem statement, all variables and given/known data
"a bucket of water is rotated in a vertical circle of radius 1.00m. What is the buckets minimum speed at the top of the circle if no water is to spill out?

2. Relevant equations
I'm not really sure where to start so.. :|

3. The attempt at a solution

I figure I must find the size of the force pulling the bucket downwards and equate that with the one pushing the water against the bucket? (I realise I've probably stuffed some force up here. this is confusing for me

If anyone could help with the equations I need then I can hopefully work this out on my own. Thanks a lot in advance

2. Mar 27, 2012

### Tui

Hey could it be that a(centrefugal or whatever :P) = v^2 / r

So I put -9.8 in for acceleration and work out v?

3. Mar 27, 2012

### azizlwl

We need to pull the water to make it rotate or centripetal force
Since at the top the gravity is pulling the water down.

If mg=mv^/2, the resultant force is just to keep it rotating and not going anywhere else.