contestada

A 19 kg solid disk of radius0.44 m is rotated about an
axisthrough its center. If the disk accelerates from rest to an
angularspeed of 2.5 rad/s while rotating1.0 revolutions, what net
torque isrequired?

Respuesta :

Answer:

0.915 Nm

Explanation:

1 revolution = 2π rad

We can use the following equation of motion to find out the acceleration acting on the disk

[tex]\omega^2 - \omega_0^2 = 2\alpha\Delta \theta[/tex]

where [tex]\omega v = 2.5 rad/s is the final angular velocity of the disk, [tex]\omega_0[/tex] = 0 rad/s is the initial velocity of the can when it starts from rest, [tex]\Delta \theta[/tex] is the angular distance traveled, [tex]\alpha[/tex] is the angular acceleration of the disk, which we care looking for:

[tex]2.5^2 - 0 = 2*\alpha*2\pi[/tex]

[tex]\alpha = \frac{2.5^2}{2*2\pi} \approx 0.5 rad/s^2[/tex]

The moment of inertia of the solid disk is:

[tex]I = \frac{1}{2}mR^2 = \frac{1}{2}19*0.44^2 = 1.8392 kgm^2[/tex]

where m is the mass and R is the radius of the disk

The net torque applied is

[tex] T = \alpha*I = 0.5 * 1.8392 = 0.915 Nm[/tex]