# Help with apparent weight problem

1. Dec 9, 2004

### vee123

I need help with a physics problem ASAP please :)

I am currently in AP Physics and we are studying centripetal force. My teacher gave me a problem that is driving me crazy because I don't know where to begin with it, and I have a test tomorrow...

Here's the problem:

An airplane pulls out of a dive in a vertical circle of radius 1.0 km traveling with a speed of 550km/h. How many times greater is the apparent weight of the pilot than his true weight?

Last edited: Dec 9, 2004
2. Dec 9, 2004

### Parth Dave

The true weight would be your weight if you were standing on the surface of the earth. This is because your weight is the normal force acting on you. If you were just standing on the surface, the normal force would oppose gravity which is the only other force acting on you. Thus, your weight would be the force of gravity, mg. In this situation, why would that be any different?

3. Dec 9, 2004

### NateTG

Here's another hint: It's important where in the loop the plane is (does the question specify that?)

4. Dec 9, 2004

### vee123

It doesn't specify where in the loop the plane is. I just want to know how to get through this problem. I'm so confused! :(

5. Dec 10, 2004

### futb0l

$$F = ma_c$$

and

$$a_c = v^2/r$$

so the ratio between the centripetal Force and the normal weight 9.8m is

$$\frac{m(v^2/r)}{9.8m} = \frac{1980000000}{1000*9.8} = 19800$$