A wheel has a rotational inertia of 16 kgm2. As it turns through 2.0 rev its angular velocity increases from 7.0 rad/s to 9.0 rad/s. Assuming the net torque is constant, how much work does that torque do?A 510 J B 130 J C 1600 J D 260 J E 400 J

Respuesta :

Answer:

Work done, W = 255.21 J

Explanation:

It is given that,

Rotational inertia of the wheel, [tex]I=16\ kg-m^2[/tex]

Angular displacement, [tex]\theta=2\ rev=12.56\ rad[/tex]

Initial angular velocity, [tex]\omega_i=7\ rad/s[/tex]

Final angular velocity, [tex]\omega_f=9\ rad/s[/tex]

Firstly finding the angular acceleration of the wheel using the equation of rotational kinematics as :

[tex]\alpha =\dfrac{\omega_f^2-\omega_i^2}{2\theta}[/tex]

[tex]\alpha =\dfrac{9^2-7^2}{2\times 12.56}[/tex]

[tex]\alpha =1.27\ rad/s^2[/tex]

Work done by the torque is given by :

[tex]W=\tau\times \theta[/tex]

[tex]W=I\times \alpha \times \theta[/tex]

[tex]W=16\times 1.27 \times 12.56[/tex]

W = 255.21 J

Out of given options, the correct option for the work done by the torque is 255.21 J. Hence, this is the required solution.

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