A CD has a diameter of 12.0 cm and is rotating at an angular velocity of 10.0 rad/sec. If the CD has a constant angular acceleration of −0.5 rad/sec², then the angular velocity of the CD after 3.0 sec is A) 5.7 rad/s. B) 6.2 rad/s. C) 7.9 rad/s. D) 8.5 rad/s. E) 9.8 rad/s.

Question

Quizplus · Accepted Answer

The angular acceleration is given as −0.5 rad/sec$^2$, which is negative because it is causing a decrease in the angular velocity. We can use the equation 
$\omega_f = \omega_i + \alpha t$
where $\omega_i$ is the initial angular velocity, $\omega_f$ is the final angular velocity, $\alpha$ is the angular acceleration, and $t$ is the time interval.

Plugging in the given values, we get:
$\omega_f = 10.0	ext{ rad/s} - 0.5	ext{ rad/s}^2 \cdot 3.0	ext{ s} = 8.5	ext{ rad/s}$

Therefore, the answer is D) 8.5 rad/s.

A CD Has a Diameter of 12