# Centripetal Force

1. May 24, 2010

### DJB1991

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

An airplane is flying in a horizontal circle at a speed of 141 m/s. The 94.2 kg pilot does not want his radial acceleration to exceed 8.88g

What is the minimum radius of the circular path?

2. Relevant equations
v^2/r

3. The attempt at a solution
141^2/.00888 kg

2. May 24, 2010

### jyothsna pb

try using v^2/r<=8.88g

3. May 24, 2010

### jyothsna pb

i dont think u have to take gravity cause its perpendicular to radial acceleration and it really has no effect (its a horizontal circle)

4. May 24, 2010

### pat666

yeah i realized that as soon as i wrote it. i was thinking centripetal acceleration and vertical circle, dont know where i got that from

5. May 24, 2010

### pat666

i dont know why they gave the pilots mass, it wont affect radial acceleration will it?

6. May 24, 2010

### pat666

with your attempt why do you have 0.00888kg? a_C =v^2/r r=141^2/9.81*8.888? = 228

7. May 24, 2010

### Jokerhelper

how does a helicopter lift-off?

8. May 24, 2010

### pat666

evidently it will but are the pilot and the plane one entity??? or are they considered as two separate masses. sorry im asking more questions than djb991 i just covered this topic and dont understand it too well.

9. May 24, 2010

### Jokerhelper

sorry, completely misread about half of that problem. then yes, the mass of the pilot seems pretty insignificant considering the mass of the airplane.

10. May 24, 2010

### pat666

is there anything you can see wrong with what ive done here? except the a_c should be a_r and there should be brackets around the bottom half.

11. May 24, 2010

### jyothsna pb

pilot n airplane r considered as one entity
pilots mass or even the whole system mass wont affect its radial acceleration as its moving in a horizontal circle
141*141/r=8.88*9.8

12. May 24, 2010

### pat666

yep thats exactly what I thought and said