A thread is tightly wrapped on two pulleys as shown in figure. Both the pulleys are uniform disc with upper one having mass M and radius R being free to rotate about its central horizontal axis. The lower pulley has mass m and radius r and it is released from rest. It spins and falls down. At the instant of release a small mark (A) was at the top point of the lower pulley. (a) After what minimum time (t_(0)) the mark will again be at the top of the lower pulley? (b) Find acceleration of the mark at time t_(0). (c) Is there any difference in magnitude of acceleration of the mark and that of a point located on the circumference at diametrically opposite end of the pulley.

A thread is tightly wrapped on two pulleys as shown in figure. Both th

1.	A thread is tightly wrapped on two pulleys as shown in figure. Both the pulleys are uniform disc with upper one having mass M and radius R being free to rotate about its central horizontal axis. The lower pulley has mass m and radius r and it is released from rest. It spins and falls down. At the instant of release a small mark (A) was at the top point of the lower pulley. (a) After what minimum time (t_(0)) the mark will again be at the top of the lower pulley? (b) Find acceleration of the mark at time t_(0). (c) Is there any difference in magnitude of acceleration of the mark and that of a point located on the circumference at diametrically opposite end of the pulley.
Answer» Answer :(a) `t_(0) = sqrt((2pi (2M + 3M)R)/(MG))` (b) `a = (2g)/(2m + 3M)N sqrt(m^(2) + (4 pi M + M + m)^(2))` (c) yes