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A wheel is turning about an axis through its center with constant angular acceleration. Starting from rest, at t = 0, the wheel turns through 8.20 revolutions in 12.0 s. At t = 12.0 s the kinetic energy of the wheel is 36.0 J. For an axis through its center, what is the moment of inertia of the wheel?

Respuesta :

Answer:

I=0.489 kg.m²

Explanation:

Given that

Initial speed of wheel (ω₁)= 0 rad/s

θ = 8.2 rev in t= 12 s

We know that

1 rev = 2π rad

8.2 rev = 16.4 π rad

θ =16.4 π rad

Lets take angular acceleration of wheel is α rad/s²

We know that if angular acceleration is constant

[tex]\theta=\omega_1t+\dfrac{1}{2}\alpha t^2[/tex]

Now by putting the values

[tex]\theta=\omega_1t+\dfrac{1}{2}\alpha t^2[/tex]

[tex]16.4\times \pi=0\times 12+\dfrac{1}{2}\alpha \times 12^2[/tex]

α =0.715 rad/s²

The final speed of the wheel at 12 s

ω₂=ω₁ + α  t

ω₂ = 0 + 0.715 x 12

ω₂ =8.58 rad/s

The final kinetic energy of the wheel

[tex]KE=\dfrac{1}{2}I\omega ^2[/tex]

[tex]36=\dfrac{1}{2}I\times 8.58^2[/tex]

I=0.489 kg.m²

This is moment of inertia of the wheel .