# Help anyone know how to do this type of problem

1. Sep 28, 2005

### tboltzsoccer

A boy of mass 41 kg rides on a playground merry-go-round at a speed of 2.0 m/s. and has to hold on with a force of 79 N to keep from flying off. What is the radius of the merry-go-round?

2. Sep 28, 2005

### arildno

What type of acceleration does the boy experience?

3. Sep 28, 2005

### Tide

Yes, a lot of people know how to do that type of problem. The real question is what have you tried so far? :)

4. Sep 28, 2005

### tboltzsoccer

F=M1*M2/R but i dono if thats right

5. Sep 28, 2005

### arildno

Do you know what your symbols mean?

6. Sep 28, 2005

### tboltzsoccer

Yes, but it seems as if there is only one mass the mass of the boy i didnt know wher the second mass would come from thats why it staryed me away from this equation but i wasnt sure what else i coudl use

7. Sep 28, 2005

### arildno

So you just pick some formula out of thin air and hope you can apply it to a given situation??

What is acceleration, what dimensions does it have?

8. Sep 28, 2005

### tboltzsoccer

its centripital acceleration

9. Sep 28, 2005

### arildno

Correct. What are the physical dimensions of acceleration?
Do you see those anywhere in your formula?

10. Sep 28, 2005

### tboltzsoccer

F=mv^2/r possibly

11. Sep 28, 2005

### arildno

That is correct.
Now, what is the unkown quantity in that equation?

12. Sep 28, 2005

### tboltzsoccer

radius so would it be .481

13. Sep 28, 2005

### tboltzsoccer

A airplane flies in a circle of radius 1.0 km at a constant speed of 1248 m/s. What is the centripetal acceleration of the airplane in km/s/s?
would the centripital accel be = (to v^2/r) or (1248^2)/1 which would be 1557504 km/s/s