# Centripetal forrce question

1. Nov 7, 2009

### kengreen

1. The problem statement, all variables and given/known data

A model airplane whose mass is 875 grams flies in a horizontal circle of radius 3.46 m at the end of a string which is at an angle 10.5 degrees below the horizontal. Find:

a) the tension in the string
b) the speed of the airplane

2. Relevant equations
Fc=T=mv^2/r Ac=v^2/r

3. The attempt at a solution
im not sure if i am given enough information to solve this problem because i dont have the acceleration or velocity

2. Nov 7, 2009

### Tzim

You have.I think you could try to analyze the forces to their components and make a relation between the vertical component of tension and the weight.

3. Nov 7, 2009

### Tzim

I hope i helped

4. Nov 7, 2009

### kengreen

i think the vertical component of tension has to cancel the weight? am i correct in where i a m going with this.

5. Nov 7, 2009

### Tzim

yeah that's very good that's the idea

6. Nov 7, 2009

### Tzim

I am sorry i misguide you.Vertical component of tension cannot cancel the weight because they are both pointing down unless i misunderstood the picture.could yuo plz draw me an image of the ecxercise?

7. Nov 7, 2009

### Tzim

if this is the case then what i told you is correct.That should be the case bacouse otherwise it would drop

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8. Nov 7, 2009

### kengreen

okay well i have the answer to the first question because i talked to my professor but i just dont understand how this is the answer. he said that it is 47.1 N.

9. Nov 7, 2009

### Tzim

Could you draw me the excercise plz?

10. Nov 7, 2009

### kengreen

there is no picture. its just a word problem. the thing that is throwing me off is that in the problem it states that the end of the string is at an angle 10.5 degrees below the horizontal.

11. Nov 7, 2009

### Tzim

If the draw is the one i made you then it is correct the 47.1.Approximatelly.Tsin10.5=Mg

12. Nov 7, 2009

### Tzim

I donnot know it should say above or else it could not be possible to rotate it would fall.ask your teacher about it

13. Nov 7, 2009

### kengreen

thank you very much

14. Nov 7, 2009

### Tzim

I donnot think i helped you very much but ok thanks