In: Physics
A turntable rotating 33 rev/m slows to a stop in 10s. If the acceleration is constant, the number of revolutions through which the turntable rotates in the 10 is?
A. 7.8
B. 1.4
C. 12.2
D. 2.7
E 6.1
Initial rotational speed of the turntable = N1 = 33 rev/min
Initial angular speed of the turntable = 1
1 = 3.455 rad/s
Final angular speed of the turntable = 2 = 0 rad/s (Comes to a stop)
Time taken by the turntable to stop = T = 10 sec
Angular acceleration of the table =
2 = 1 + T
0 = 3.455 + (10)
= -0.3455 rad/s2
Negative as it is deceleration.
Angle through which the turntable rotates in 10 sec =
= 1T + T2/2
= (3.455)(10) + (-0.3455)(10)2/2
= 17.275 rad
Number of revolution made by the turntable in 10 sec = n
n = 2.7 rev
Number of revolutions through which the turntable rotates in 10 sec = 2.7 rev