KCET2014PhysicsLaws of Motion
A rotating wheel changes angular speed from ( 1800 rpm ) to ( 3000 rpm ) in ( 20 ~s ). What is the angular acceleration assuming to be uniform ?
Options
- A( 60 ) п rad s ( ⁻² )
- B90п rad s ( ⁻² )
- C( 2 rad s⁻² )
- D40п rad s ( ⁻² )
Correct answer
C. ( 2 rad s⁻² )
Step-by-step solution
For angular speed of ( 1800 rpm ) ( ₁=2 f₁=2 ( 1800 60 )=60 rad s⁻¹ ) For angular speed of ( 3000 rpm ) ( ₂=2 f₂=2 ( 3000 60 )=100 rad s⁻¹ ) Therefore, angular acceleration ( = ₂- ₁ t = 100 -60 20 ) ( = 40 20 =2 ) Thus, angular acceleration of rotating wheel ( =2 rads ⁻² )