Im working on this masteringphysics problem. I dont know the answer.


I have a rod of length 0.8m. The total amount of torque on this rod is0.8 torque( i came up with this value from the image provided) in the counterclock wise(+pos).

Starting at rest, the rod starts to move. I need to determine the angular momentum after6seconds, and I think it wants me to use the torque_net = dl/dt law to solve it.

I cannot use T=I*alpha because I do not know the mass.

The answer is 4.8 kg * m^2/s..



If you are familiar with MasteringPhysics, you can google the problem. It is named Spinning the Wheels: An Introduction to Angular Momentum

This post was edited by thestoryofisaac on Nov 9 2013 02:34am

you know torque
t=i*alpha
.8 torque = i*alpha

alpha=.8/i

integrate alpha to get omega, rational velocity

at t= 6, omega,w= 4.8/i
momentum = mass*velocity
angular momentum = i * rotational v


This post was edited by saber_x3 on Nov 9 2013 11:40am

I don't understand this part.

This post was edited by thestoryofisaac on Nov 9 2013 05:31pm

rotational*
integrate angular accel to get angular velocity

I figured it out, finally.

L= Iw
w=at
a=T/I

w = T/I*t
L = I*(T/I*t)
L=T*t
L=0.8*6
L=4.8