Two cars leave the same intersection at the same moment

MATHEMATICS · Multi-part · AP · Calculus AB · Contextual Applications of Differentiation · Contextual Applications of Differentiation

Problem

Two cars leave the same intersection at the same moment. Car A travels due north at a constant speed of 50 km/h, and Car B travels due east at a constant speed of 120 km/h. Let tt be the time in hours after the cars leave the intersection, and let s(t)s(t) be the straight-line distance (in km) between the two cars at time tt. (a) Express s(t)s(t) in terms of tt using the given information. (b) Calculate dsdt\dfrac{ds}{dt} when t=160t=\dfrac{1}{60} h (10 s). Include appropriate units. (c) Interpret the sign and magnitude of your answer to part (b) in the context of the motion of the two cars.

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