A wrench with a length of 42cm is being used to unscrew a 72cm bolt. If a torque of 18Nm is needed to overcome the friction keeping the bolt in place, what is the minimum torque that must be applied to the wrench to unscrew the bolt?
1 Answer
Explanation:
I assume the question is meant to ask what is the minimum force required to unscrew the bolt.
Torque is given by the equation:
τ=rFsinϕ where
F is the applied force,r is the distance from the pivot (axis of rotation) that the force is applied, andϕ is the angle at which the force is applied.
We can rearrange the equation for torque to find
F=τrsinϕ
We are provided the following information:
r=42cm=0.42m
τ=18Nm
And it is implied that
Note that I am not including the radius of the bolt in the measurement of the total radius because I am assuming that this is the radius of the body of the screw and not the head of the screw.
Therefore, we have:
F=18Nm0.42m
=42.86N
≈43N