Circular Motion Plane Loop

1. Apr 2, 2008

JonathanSnow

1. The problem statement, all variables and given/known data
someone is flying a plane and he is being chased and at the bottom of the loop his guages say he is traveling at 180km/h he is sitting on a bathroom scale which says he weighs 4 times what he normally does, what is the radius of the loop in meters?

2. Relevant equations
Fc=Fn ?
R=v^2/g

3. The attempt at a solution
well 180km/h is 50m/s and since he is 4 times as heavy the acceleration due to gravity will be 4 times greater? so i used the formula and it comes out as 63.71 m which seems unbelievable so i figured id ask, probably somthing stupid im doing wrong

thanks

2. Apr 2, 2008

3. Apr 2, 2008

JonathanSnow

thanks i think its right :)

4. Apr 2, 2008

Dr. Jekyll

Aren't the forces on the body at the bottom of the loop $\vec{F_{cf}}+\vec{W}=4\vec{W}$? Then we get different acceleration.