- #1
RoyalFlush100
- 56
- 2
Homework Statement
"A drum of 60-mm radius is attached to a disk of 120-mm radius. The disk and drum have a total mass of 6 kg and a combined radius of gyration of 90 mm. A cord is attached as shown and pulled with a force P of magnitude 20 N. The disk rolls without sliding. Determine the minimum value of the coefficient of static friction compatible with this motion."
I have attached the image below
Homework Equations
T = Iα
The Attempt at a Solution
Known forces:
W = (6 kg)(9.81 N/kg) = 58.86 N, downwards, at G
First, because the system is not accelerating in the y direction we know that:
N = W - P = 58.86 - 20 = 38.86 N
Friction then will equal:
f = 38.86μ
Moment of Inertia:
I = (6 kg)(0.09 m)^2 = 0.0486 kg*m^2
So, now the sum of all torques:
T = -(0.12 m)(38.86μ) = (0.0486 kg*m^2)α
I'll need angular acceleration of the middle disc. What would I need to do to find that? Also, I'm assuming there has to be another horizontal force (presumably at G), how would that factor in?
Attachments
Last edited: