Rotational Motion Speed at the top of the loop

[physgrl]

Homework Statement

12. A motorcycle travels around a vertical 12 m radius loop. What is its speed at the top of the loop if the normal force exerted by the seat on the driver is equal to ¼ of his weight?

a. 7 m/s

b. 8.1 m/s

*c. 9.4 m/s

d. 15 m/s

e. 88 m/s

Homework Equations

F=ma
W=mg
T=F-W
a=v²/r

The Attempt at a Solution

I did (1/4)W=m(v²/r)-W and I got 12.1 m/s

 

[LawrenceC]

I get the same answer as you.