Two blocks are connected by a massless rope that passes over a pulley. The 4.0 k
ID: 2212725 • Letter: T
Question
Two blocks are connected by a massless rope that passes over a pulley. The 4.0 kg block is 2.0 meter above the floor while the 2.0 kg block is resting on the floor. The mass of the pulley is 2.0 kg and it diameter is 12.0 cm. As the pulley turns, assume there is no slippery between the rope and the pulley. If the blocks are released from rest, how long does it take the 4.0 kg block to reach the floor for the following two scenarios: (A): if there is no friction when the pulley turns (B) if there is friction at the axel of the pulley, and exerts a torque of magnitude 0.5 N
Explanation / Answer
4*9.81-T1=4*a T2-2*9.81=2*a (T1-T2)*0.06=0.5*2*0.06^2*a/0.06 T1-T2=a a=2.8 m/s^2 s=2 m s=0.5*a*t^2 t=1.2 sec friction is present (T1-T2)*0.6-0.5=0.5*2*0.06^2*a/0.06 T1-T2=a+0.83 a=2.68 m/s^2 2=0.5*2.68*t^2 t=1.22 sec