A solid disk of radius rests on a frictionless axle
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Torque and Rotational Dynamics · Torque and Rotational Dynamics
Problem
A solid disk of radius 0.20m rests on a frictionless axle. Beginning at t=0, it experiences the following piecewise-constant angular acceleration:
• For 0≤t<1.5s, the angular acceleration is +8.0rads−2.
• For 1.5s≤t≤4.5s, the angular acceleration is −2.0rads−2.
Initially the disk is at rest and rotates in the positive direction throughout the interval considered.
(a) Determine the angular speed of the disk at t=1.5s. Show all work.
(b) Determine the angular speed of the disk at t=4.5s. Indicate clearly whether the disk is still rotating in the positive direction.
(c) Calculate the total angular displacement of the disk from t=0 to t=4.5s.
(d) Using your result from part (c), find the linear distance traveled by a point on the rim of the disk during the 4.5s interval.
(e) Explain, without additional calculation, whether the disk ever comes to a complete stop during the second interval of motion. Support your answer with quantitative reasoning from earlier parts.