Torque, Torsion and Theory Question

The size of a shaft, subjected to widely varying torques, is calculated based on the mean torque or maximum torque normally? (this type of question i very curiois)

lptd of torque and power questions recently.....is Google broken right at exam time?

Not sure whether google is broken. Now is exam period. I guess this is why alot of people asking question and I think power and torque must be a *popular* topic.

When designing anything you will want to design it to withstand maximum stresses it is going to encounter....and then usually add an accepted excess for safety....

Why not start by telling us what you think the answer is.

You must have some idea.

It seems very obvious to me.

If you have to lift widely varying loads with a string would you use a string that can lift the average load or one that can lift the largest load? Why?

Thanks Lyn and everyone else

I get what you trying to said, thanks

I think is the max torque

steel is stronger am i right to choose

Stress = force/Area should be same regardless of material.

Strain is material's reaction to stress (depends on material)

What has this to do with torque and torsion?

It's a bit of a silly question as it says σ_steel = σ_brass in the top left corner so the answer has been given, apart from being elementary (taking σ = stress).

Assuming ε = strain = change of length/original length - this depends on the elastic modulus E of the 2 materials. ε_steel = ε_brass is wrong as E differs. I leave you to find which is higher but it doesn't take much knowledge of materials to have a good idea.

I wonder if whoever set the question knows what he's doing.

Ok, start here

https://www.youtube.com/watch?v=8Gv0H-vPoDc

Nice. I didn't know this guy was still around. I still remember "Eat It".