Question

A rotating flywheel can be used as a method to store energy. If it is required that such a device be able to store up to a maximum of 1.00 ´ 106 J when rotating at 400 rad/s, what moment of inertia is required?

options:

1)

50 kg×m2

2)

25 kg×m2

3)

12.5 kg×m2

4)

6.3 kg×m2

5)

5.4 kg×m2

Answer 1

(3).I = 12.5 kg.m²

Step-by-step explanation:

Given that

maximum stored energy E

E= 1 x 10⁶ J

Angular speed ,ω = 400 rad/s

We know that energy stored in flywheel given as

`E=(1)/(2)I\omega^2`

I=Moment of inertia of the flywheel

Now by putting the values

`10^6=(1)/(2)* I* 400^2`

`I=(2* 10^6)/(400^2)`

I = 12.5 kg.m²

Therefore the answer will be (3).

I = 12.5 kg.m²