Question

The bolts on a car wheel require tightening to a torque of 90 N*m. If a 30 cm long wrench is used, what is the magnitude of the force required when the force applied at 53 degrees to the wrench?

Answer 1

\[Tau=Fx=Fcos(90-53)30cm \frac{ 1m }{ 100cm }=90Nm \rightarrow F=\frac{ 90Nm }{ \cos(37)0.3m }=375.64N\]

Answer 2

so pretty much work=torque?

Answer 3

Nonono because then torque would be in Joules. The thing is that torque is a dot product so it is not like work. In torque you multiply a force perpendicular to the wrench arm (I'm Colombian so I don't have it clar how you call "el brazo de palanca". That's why I had to transform the force by multiplying the cos(90-53). They have to be perpendicular to do the dot product and to get the result in a different dimension, that's why it is Nm and not J. Well that's at least how I understand the difference between torque and work, but believe they are different.

Answer 4

ok

Answer 5

Oh I found the formula. torque=rFsinx but I got 3756.4 not 375.64 why is that? Am I right or are you right (I'm assuming you're right but I just want to make sure and find out why I got a different answer)

Answer 6

I just did it again, and I got the same 375.64, are you sure you did the convertion from cm to m right?

Answer 7

yeah i see that lol my fault

Answer 8

:)