- #1
Jalo
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Homework Statement
the mass, M, of the disk is 20kg, the radius is r and the force applied, F, in the periphery of the disk is 9.8N. How much is the angular acceleration?
If I add a mass (m1) of 1kg to the thread what will be the angular acceleration?
Homework Equations
I think those are relevant to my problem:
Moment of inertia of a disk: I=0.5*m*r^2
Torque=Force*radius*sin(tetha)
angular acceleration=Torque/Moment of inertia
The Attempt at a Solution
a) I=.5mr^2 ⇔I=2.5
Torque=9.8*0.5=4.9N*m
angular acceleration=4.9/2.5 = 1.96 rad/s^2
I think this one is correct
b) Since it was added another mass I tought that the total force would be F+T, tension being equal to the force of the mass*gravity (9.8). Then:
I=2.5
Torque=9.8N*m
angular acceleration=9.8/2.5=3.92 rad/s^2
The correct answer is 1.8 rad/s^2. any hints would be highly appreciated!
Thanks.
D.