Engineering Maths

[scraggle]

Please forgive me if I have posted this in wrong section. I have to complete maths problems but I am not getting anywhere, can someone explain how I figure this out?

Gear A and Gear B are intermeshed, A having a radius of 200mm and B a radius of 150mm. Gear A starts from rest and rotates with a constant angular acceleration of 2 rad/s2. How do I determine the the angular velocity and angular acceleration of Gear B after A has completed 10revs?

I understand how to work out basic ang vel and acc but don't quite understand the after 10revs bit and the intermeshed bit!

[scotstone]

Remember all lengths must be in metres. The unit for J is m^4. Try again.

[scraggle]

ok i getting a really small figure like 0.0000003m^4. I got this funny feeling i have this all wrong!

[scraggle]

I shall have to continue tomorrow now. Hope you will still have the time for me then.... it must be like pulling teeth for you!! It is appreciated I assure you.

[scotstone]

You have the correct order of magnitude because J is always a small value but the answer is not quite correct.

You should have :-

J = Pi( 0.05^4-0.037^4)/32

[scraggle]

Of course, that is me using the wrong internal diameter. So the Polar Moment of Inertia is 0.0000004m^4

[scotstone]

Approximately. You should try to use standard form ie 4.295x10^-7m^4.

Now using the torsion formula ie

Torque/Pol Mom of Iner = shear stress/radius calculate

the maximum allowable torque.

[scraggle]

Which radius am i to use within the formula (is it the outer - the inner again)? and do you use 15 M.Pa as a simple number 15? The standard forms are not something i am over familiar with.

[scotstone]

I can't understand how you expect to complete an engineering course without being familiar with standard form or engineering multiples such as M,k,G.

Although I am happy to help I don't think I'm doing you any favours by doing your assignments for you. Get back to me when you have mastered the basics.