A small drone travels along a straight line that we define as the positive -axis…

PHYSICS · Multi-part · A Level · Physics · Mechanics and materials · Mechanics and materials

Problem

A small drone travels along a straight line that we define as the positive xx-axis (forward direction). The drone’s velocity is measured at three different clock readings: • At t=0 st=0\,\text{s}, v=+2.0 m s−1v=+2.0\,\text{m}\,\text{s}^{-1}. • At t=5.0 st=5.0\,\text{s}, v=+8.0 m s−1v=+8.0\,\text{m}\,\text{s}^{-1}. • At t=12.0 st=12.0\,\text{s}, v=−3.0 m s−1v=-3.0\,\text{m}\,\text{s}^{-1} (the drone is now moving backward along the xx-axis). Assume that between these clock readings the velocity changes uniformly during each interval, but the acceleration need not be the same in the two intervals. (a) Determine the average acceleration of the drone during the first interval from t=0 st=0\,\text{s} to t=5.0 st=5.0\,\text{s}. (b) Determine the average acceleration of the drone during the second interval from t=5.0 st=5.0\,\text{s} to t=12.0 st=12.0\,\text{s}. (c) Calculate the overall average acceleration of the drone for the entire 0–12 s0\text{–}12\,\text{s} time period. (d) Assuming the acceleration found in part (b) remained constant throughout the 5.0–12.0 s5.0\text{–}12.0\,\text{s} interval, derive an algebraic expression for the instant t0t_0 (measured from t=5.0 st=5.0\,\text{s}) at which the drone momentarily came to rest before reversing direction. Then compute the numerical value of t0t_0.

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