A river is wide and flows due east with a speed of

PHYSICS · Single correct · AP · Physics 1: Algebra-based · Kinematics · Kinematics

Problem

A river is 200 m200\,\text{m} wide and flows due east with a speed of 3 m s−13\,\text{m\,s}^{-1}. A boat can move at 5 m s−15\,\text{m\,s}^{-1} in still water and is aimed due north (perpendicular to the banks). Which pair gives the time taken to reach the opposite bank and the downstream displacement of the boat, both measured relative to the riverbank? (a) 25 s,  75 m25\,\text{s},\;75\,\text{m} (b) 40 s,  120 m40\,\text{s},\;120\,\text{m} (c) 33 s,  100 m33\,\text{s},\;100\,\text{m} (d) 50 s,  150 m50\,\text{s},\;150\,\text{m}

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