Question

A circular disc is rotating about its own axis with a constant angular acceleration.If its angulat velocity increases fron 210 rpm to 420rpm during 21 rotation then the angular acceleration of the disc is

Answer 1

Answer:

The answer will be 5.5 rad /s^2

Explanation:

According to the problem it is given that the angular velocity increases

Let the initial angular velocity ω1= 210 rpm = 7/2 rps

Now we will convert the rps to angular velocity,

we know θ = 2 π x rps = 2 xπ  x 7/2 = 22

Again Let the final angular velocity ω2= 420 rpm = 7 rps

Now we will convert the rps to angular velocity,

we know θ = 2 π x rps = 2 x π x 7 = 44

Now as given the number of rotations are 21

Now we will convert the rps to angular velocity,

we know θ = 2 π x rps = 2 x π x 21 = 132

Now we know that the

angular acceleration = (final angular velocity)^2-( initial angular velocity)^2/2θ

=> a = (ω2)^2 -(ω1)^2/2θ

        =(44)^2 -(22)^2/ 2 x 132 = 5.5 rad /s^2