A small disk of radius 0.5 m is mounted coaxially with a larger disk of radius 1
ID: 1609048 • Letter: A
Question
A small disk of radius 0.5 m is mounted coaxially with a larger disk of radius 1.5 m. The disks are securely fastened to each other and the combination is free to rotate on a fixed axle that is perpendicular to a horizontal frictionless table top. The rotational inertia of the combination is 9.5 kg m2. A string is wrapped around the larger disk and attached to a block of mass 7, on the table. Another string is wrapped around the smaller disk and is pulled with a force 99 N along a tangential direction of the disk. Determine the acceleration of the block.
Explanation / Answer
Here
T=ma
-TR2+FR1=Ia/R2
maR2+Ia/R2=FR1
a=FR1/[mR2+(I/R2)]
a=99*0.5/[7*1.5+(9.5/1.5)
a=2.94 m/s2