An electric fan is turned off, and its angular velocity decreases uniformly from 550 rev/min to 180 rev/min in a time interval of length 4.30 s.
a.) find the angular acceleration in revolutions per second per second.
= -1.43 rev/s^2
b.) find the number of revolutions made by the fan blades during the time that they are slowing down in part a.
= rev
c.) how many more seconds are required for the fan to come to rest if the angular acceleration remains constant at the value calculated in part a?
= s

(a)

(b) 4.17 rev

(c) 6.40 sec

Explanation:

We have given the angular velocity of fan decreases from 550 rev/min to 180 rev/min

So initial angular speed

Final angular speed

Time is given as t = 4.3 sec

(a) We know that angular acceleration is given by

(b) We know the relation \Theta =\omega _0t+\frac{1}{2}\alpha t^2=9.166\times 4.3-\frac{1}{2}\times 1.43\times 4.3^2=26.1935rad=\frac{26.1935}{2\pi }=4.17rev

(c) Now final angular velocity

So time

when it gains or loses electrons

the working equation for the angular size is the product of the physical size and 360 degrees divided by the product of two pi and distance from earth. the minimum size would be 0.559 degrees while the maximum size would be 0.49 degrees.