# Newtons Laws Question

1. Oct 30, 2004

### nissan300zxs

Having trouble with a homework problem on Newtons Laws, would appreciate any help:
An airplane flies in a loop (a circular path in a vertical plane) of radius 150m. The pilot's head always points toward the center of the loop. The speed of the airplane is not constant; the airplane goes slowest at the top of the loop and fastest at the bottom. a)At the top of the loop, the pilot feels weightless. What is the speed of the airplane at this point? b) At the bottom of the loop, the speed of the airplane is 280km/h. What is the apparent weight of the pilot at this point? His true weight is 700N.

Thanks in adavance for any assistance.

2. Oct 30, 2004

### Sirus

This will be moved to homework section promptly, but anyways...

Please show us what you have done so far. Try beginning with a free-body diagram for each position. What can you deduce about the net force acting on the pilot if he feels weightless? You may find the following formulas useful:
$$F_{net}=ma$$
$$F_{centripetal}=\frac{mv^{2}}{r}$$

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