Question

Following a collision in outer space, a copper disk at 800°C is rotating about its axis with an angular speed of 29.0 rad/s. As the disk radiates infrared light, its temperature falls to 20.0°C. No external torque acts on the disk. (a) Does the angular speed change as the disk cools? It stays the same. It increases. It decreases. Correct: Your answer is correct. Explain how it changes or why it does not. to maintain the conservation of angular momentum, the angular speed must increase. Score: 0.83 out of 0.83 Comment: (b) What is its angular speed at the lower temperature? 29.0 Incorrect: Your answer is incorrect. Your response is within 10% of the correct value. This may be due to roundoff error, or you could have a mistake in your calculation. Carry out all intermediate results to at least four-digit accuracy to minimize roundoff error. rad/s Need Help? Read It

Answer 1

The angular speed of the copper disk changes as it cools due to the conservation of angular momentum. The new angular speed can be calculated using the equation angular speed = initial angular speed * (initial temperature / final temperature), which yields 1160 rad/s.

Step-by-step explanation:

The angular speed of the copper disk does change as it cools. This is because the conservation of angular momentum requires the angular speed to increase as the disk radiates infrared light and its temperature decreases. In other words, to maintain the same angular momentum, the slower rotating disk must spin faster as it cools.

In this case, the initial angular speed of the disk is 29.0 rad/s and the final temperature is 20.0°C. To find the new angular speed, we can use the equation:

angular speed = initial angular speed * (initial temperature / final temperature)

Plugging in the values, we have:

angular speed = 29.0 rad/s * (800°C / 20.0°C) = 1160 rad/s

Therefore, the new angular speed of the disk at the lower temperature is 1160 rad/s.