# 313 Maximum Torque That Can be Applied to a Hollow Steel Shaft

ahsan

how find the value of L?? in the question I don't found the value of L?? but in solutions I see the value L-1000

Hi there Ahsan! I think they used 1000 to make the imaginary "L" into a mm unit so that the equation is suitable to the formula. You're welcome in advance!

Jhun Vert

The length is actually given if you read it carefully. It is indicated in the maximum angle of twist which is 0.5 deg/m. That is for every 1 meter (or 1000 mm), you are limited to 0.5 deg rotation.

CheatPls

Is there no need to convert 0.5 deg/m to deg/mm ? ^^; i tried solving it on my own but noticed you didn't so i was wondering

Jhun Vert

There is no need if your L = 1000 mm in the right side of the equation, but if your L = 1 mm, then you should convert that that angle to deg/mm.

CheatPls

Oh and uhh it says in the problem to <strong>Determine the maximmum torque</strong> but why do we choose the smaller one???

Jhun Vert

It actually means the maximum safe torque. If you load the larger larger torque, itwill resist the shear, but, it will twist beyond the allowable.