Torque and Chrome

Torque on Wrench - Vectors Problem?

A wrench 35 cm long lies along the positive y-axis and grips a bolt at the origin. A force is applied in the direction <0,4,-3> at the end of the wrench. Find the magnitude of the force needed to supply 50 J of torque to the bolt. I believe I need to use the cross product of the length and the direction somehow... I'm just really not sure how to set this problem up.

Public Comments

1. F = m unit<0,4,3> = m < 0, 4/5, -3/5> The lever from the point of the force to the bolt is 0.35 <0,-1,0> F x L = .35 m <0, 4/5, -3/5> x < 0, -1, 0> = 0.35 m < -3/5, 0 ,0> 50 J = .35(3/5)m m = 5(50)/1.05 = 238.0952381 Newtons