A fly wheel is accelerated uniformly from rest and rotates through 5 rad in the first second. The angle…

A fly wheel is accelerated uniformly from rest and rotates through 5rad in the first second. The angle rotated by the fly wheel in the next second, will be :
  1. 7.5rad
  2. 15rad
  3. 20rad
  4. 30rad

Solution

Here the angular acceleration is constant, so we have,

θ=ωt+12αt2.

When flywheel is rotated from rest in the first second, then θ1=12α12=5 rad 

α=10 rad s-2

The angle turned by flywheel in the next second is θ2=12α22=12104=20 rad s-2

Thus, the angle turned during next second is θ=20-5=15 rad

Asked in: JEE Main 2022 (24 Jun Shift 2)

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