MCAT Question A Day - 3/13/14 - Answer!
A car drives around a circular track at a constant speed of 20 m/s. If the track is flat and has a radius of 200 m, what is the acceleration of the car?
A. 2.0 m/s2
B. 10 m/s2
C. 1.0 m/s2
D. 0.10 m/s2
The correct answer is (A). The speed is constant but the direction of the car is constantly changing; thus, the velocity is constantly changing, which in turn means the car undergoes acceleration. Since only the direction, but not the magnitude of the velocity, is changing, only the radial acceleration component is nonzero. The tangential acceleration component is zero.
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The correct answer is (A). The speed is constant but the direction of the car is constantly changing; thus, the velocity is constantly changing, which in turn means the car undergoes acceleration. Since only the direction, but not the magnitude of the velocity, is changing, only the radial acceleration component is nonzero. The tangential acceleration component is zero.
ar = v2 / r = (20m/s)2 / 200m = 2.0m/s2
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