Calc 3
posted by Raquel .
A wrench .9m long lies along the positive yaxis, and grips a bolt at the origin. A force is applied in the direction of (0,1,3) at the end of the wrench. Find the magnitude of the force in newtons needed to supply 100 J of torque to the bolt.
This is the formula i have:
T=r x F Can anybody point me in the right direction?

T=100J
r=.9j
F=F (0i+1j+3k)/sq root 1^2+3^2)
Replace the values on the formula and solve for F. 
A wrench 0.4 meters long lies along the positive yaxis, and grips a bolt at the origin. A force is applied in the direction of ⟨0,1,5⟩ at the end of the wrench. Find the magnitude of the force in newtons needed to supply 100 newtonmeters of torque to the bolt.