A thin, uniform rod of length 0.80 m and mass 1.5 kg is pivoted about a frictionless…
PHYSICS · Multi-part · AP · Physics 1: Algebra-based · Torque and Rotational Dynamics · Torque and Rotational Dynamics
Problem
A thin, uniform rod of length 0.80 m and mass 1.5 kg is pivoted about a frictionless hinge at its left end so that it can rotate freely in a vertical plane. Initially the rod is held horizontally and at rest. At the instant it is released, a horizontal 3.0 N force is applied to its right end, directed to the left.
(a) Calculate the magnitude of the torque exerted on the rod by the applied force immediately after release.
(b) The rod’s moment of inertia about the hinge is 31ML2. Determine the rod’s initial angular acceleration, including its direction.
(c) At the same instant, identify the direction of the rod’s instantaneous angular velocity. Explain how the sign of angular acceleration you found in part (b) informs whether the magnitude of the angular velocity will increase or decrease during the next short time interval.