A turntable initially rotates at

PHYSICS · Subjective · AP · Physics 1: Algebra-based · Torque and Rotational Dynamics · Torque and Rotational Dynamics

Problem

A turntable initially rotates at 3313 rev min−133\tfrac{1}{3}\,\text{rev\,min}^{-1}. A mark on its rim is observed for a total time of 2.5 min2.5\,\text{min}. At the instant t=1.5 mint = 1.5\,\text{min}, the rotation rate is suddenly increased (instantaneously) to 6623 rev min−166\tfrac{2}{3}\,\text{rev\,min}^{-1} and remains constant at this higher value for the remainder of the observation. Ignore the brief transition interval. (a) Calculate the angular displacement of the mark during the first 1.5 min1.5\,\text{min}. (b) Determine its angular displacement during the next 1.0 min1.0\,\text{min} while the turntable is rotating at the higher speed. (c) Express the total angular displacement for the entire 2.5 min2.5\,\text{min} observation as: (i) the number of complete revolutions, and (ii) the additional angle (in degrees) beyond those whole revolutions. (d) If the radius of the rim is 0.15 m0.15\,\text{m}, calculate the total distance travelled by the mark along the circular path during the 2.5 min2.5\,\text{min}. Provide detailed calculations and state your answers with correct units.

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