Finding the radius of an arc

[jelynell]

Homework Statement

Im having trouble figuring out which equation to use for this problem. The problem states: "Consider a pilot at the lowest point of a circular arc banking upward. Find the tightest radius arc that an untrained individual can fly ( a total of +5 G, G standing for the normal force the accelerating aircraft is exerting on the pilot. For example, 6G force would be exerting a normal force 6 times the persons weight.). They are traveling at 700m/s.

Homework Equations

Since this involves normal force, I thought I could somehow use: the sum of F=ma and Fw=mg
In addition I tried using a=v squared/r and/or v=2(pi)r/T

The Attempt at a Solution

In an attempt to try to solve this problem I tried using Fn= 5N in the equation Fn-Fw=ma By finding acceleration I could then use a=v squared/r to solve for r, but I don't have enough variables to plug into the first equation.
So I tried using v=2(pi)r/T giving me 700m/s=2(pi)r/T so then I could find r this way, However I do not know the value for T.
Am I using the completely wrong equations? If not, what am I doing wrong?

 

[LowlyPion]

Welcome to PF.

I'd suggest drawing a diagram and making sure how much acceleration the plane will impart and how much is just a result of gravity.

As to your equation, you want to consider the centripetal acceleration here.

 

[Delphi51]

I could then use a=v squared/r to solve for r

I think you have it here. r = v^2/a
Your acceleration is 5 times 9.81.