Identify the increasing order of the angular velocities of the following
1. Earth rotating about its own axis
2. Hour's hand of a clock
3. Second's hand of a clock
4. Flywheel of radius 2 m making 300 rpm

Options

A. 1,2,3,4
B. 2, 3, 4, 1
C. 3,4, 1,2
D. 4, 1,2,3

Answer

(a)

Explanation

1. Earth rotating about its own axis,
Time period. `T=24 xx 60 xx 60 = 86,400 sec`  Angular velocity,`omega=(2pi)/(T)=(2pi)/(86,400)rad//s`
  Hour's hand of a clock
`T=12xx 60xx 60 = 43200 sec`
`omega=(2pi)/(43200)rad//s`
3. Second's hand of a clock
`T= 1 xx 60 = 60 s`
`omega=(2pi)/(60) rad//sec`
4`omega=2pin=2pixx(300)/(60)=5xx2pi`
Therefore, the increasing order is 1 <2<3<4