Question

When a ceiling fan is switched off, its angular velocity falls to half while it makes 36 rotations. How many more rotations will it make before coming to rest (Assume uniform angular retardation)​

Answer 1

So it takes the help of the compression which is different then others. Hope this will help u

Answer 2

Answer:

12

Explanation:

Let the initial angular velocity of the fan be w

∴ Its angular velocity when the fan makes 36 rotation       w

1

​

=0.5w

Using        w

2

2

​

−w

1

2

​

=2αS                 where  S=2π(36) radian

∴    (0.5w)

2

−w

2

=2α×2π(36)            ⟹4πα=

36

−0.75w

2

​

Let the fan makes n more rotation before coming to rest.

Using        w

3

2

​

−w

2

2

​

=2αS                          where  S=2πn radian   and   w

3

​

=0

∴    0−(0.5w)

2

=2α(2πn)

OR        −0.25w

2

=

36

−0.75w

2

​

×n                      ⟹n=12