A ceiling fan is turned on and reaches an angular speed of 60 rev/min in 30 s.It is then turned off and coasts to a stop in 60 s.In the one minute of rotation,through how many revolutions did the fan turn?
A) 90
B) 180
C) 900
D) 120
E) 240

Question

A ceiling fan is turned on and reaches an angular speed of 60 rev/min in 30 s.It is then turned off and coasts to a stop in 60 s.In the one minute of rotation,through how many revolutions did the fan turn?
A) 90
B) 180
C) 900
D) 120
E) ​240

Quizplus · Accepted Answer

The fan accelerates to 60 rev/min in 30 s, averaging 30 rev/min during this time, resulting in 15 revolutions. It then decelerates from 60 rev/min to 0 in 60 s, averaging 30 rev/min, resulting in 30 revolutions. Total revolutions = 15 + 30 = 45.

A Ceiling Fan Is Turned on and Reaches an Angular