Disk A in (Figure 1) has radius RA and thickness h and is initially rotating clo
ID: 1293841 • Letter: D
Question
Disk A in (Figure 1) has radius RA and thickness h and is initially rotating clockwise, as viewed from above, at ?i / 2. Disk B, made of the same material as A, has radius RB=RA/2 and thickness h and is initially rotating counterclockwise at ?i . The two disks are constrained to rotate about the same axis, which runs through their centers. There is friction between the disks, and so once B slides down and touches A, they spin at the same rotational speed.
A.
What is their common final rotational velocity?
Express your answer in terms of some or all of the variables ?i and RA. Enter positive value if the rotation is counterclockwise and negative value if the rotation is clockwise.
B.
If the frictional force is the only force that causes the system to lose energy, what is the fractional change in the kinetic energy?
Express your answer using two significant digits.
Explanation / Answer
I *wi/2 - I/16 * wi = (1 + 1/16) *wf
wf = 0.4117 wi
b ) -(17*16)*0.5*I *wi*wi *(0.4117*0.4117) + {0.5 *I*wi*wi/4)} + (0.5*I/16 * wi*wi} / {0.5 *I*wi*wi/4)} + (0.5*I/16 * wi*wi}
0.423 fraction loss in energy check this modified answer thank u and rate it plss