# Pail homework problem

1. Nov 27, 2005

### nrc_8706

a pail of water is rotated in a vertical circle of r=1.4m acceleration of gravity 9.8m/s^2

the pail is rotated at a constant rate so it has the minimum speed at all points along its circular path. the water has a mass m.
when the pail is at the bottom of the circle, what is the magnitude of the force exerted by the water on the bottom of the pail?

F=ma=0 since it is at a constant rate right?

but then i dont know what to do next?

2. Nov 27, 2005

### johnw188

Nay! Draw out your free body diagrams, that should help.

Also, I notice a lot of people making this mistake. Saying F = ma is rarely true. Always remember to add your sigma

$$\sum F = ma$$

3. Nov 27, 2005

### nrc_8706

?

normal force is upward and weight is downward

Fnet=Fn-mg?

4. Nov 27, 2005

### nrc_8706

Help!!!!

CAN ANYBODY HELP ME?!!!!!

5. Nov 27, 2005

### stuplato

the water exerts two forces onto the pail... can you name them?

6. Nov 27, 2005

### nrc_8706

its weight and........

7. Nov 27, 2005

### stuplato

Centripital Force

8. Nov 27, 2005

### nrc_8706

....

ok so its F=4mg or F=2mg?

9. Nov 27, 2005

### stuplato

Centripital force is defined by equation:

Fc = (m*v^2)/r

10. Nov 27, 2005

### nrc_8706

gracias

:uhh: thanks for everything but im just not understanding

11. Nov 27, 2005

### stuplato

What is your current curriculum/topic in class?

12. Nov 27, 2005

### nrc_8706

Dynamics Of Uniform Circular Motion