Section14.8Challenge - Rotational Energy and Angular Momentum
Explanation14.8.1.Spool Competition.
You and your friend are in a competition to see which spool will reach the top of a frictionless ramp first. There are two spools: One spool has a thread wrapped many times around it so that as it is pulled up the ramp, it will rotate, and the other spool has a thread fixed at one point so that it will not rotate. Assume the thread is ideal and you and your friend can pull with the same tension.
Part A: Which spool do you want to choose in order to win?
Part B: If instead the competition was about which spool has the most energy at the top of the ramp, would you choose a different spool?
A*R*C*S14.8.2.Brick on a Disc.
A \(100 \mathrm{~kg}\) disc with radius \(1.6 \mathrm{~m}\) is spinning horizontally at \(25 \mathrm{~rad/s}\text{.}\) You place a \(20 \mathrm{~kg}\) brick quickly and gently on the disc so that it sticks to the edge of the disc. Determine the final angular speed of the disc-brick system. Discuss whether the kinetic energy of the system increases, decreases, or remains the same.
Activity14.8.3.Metacognitive Reflection: Models.
You have now finished adapting your model for motion to include rotational motion. Consider again the questions from Models Steps. Considering specifically the process of adapting your model to include rotational motion, are your answers to these questions different than they were when you began this process?
