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In a drag race, the position of a car as a function of time is given by x = bt2, with b = 2.000 m/s2. In an attempt to determine the car’s velocity midway down a 400-m track, two observers stand at the 180-m and 220-m marks and note when the car passes, (a) What value do the two observers compute for the car’s velocity over this 40-m stretch? Give your answer to four significant figures. (b) By what percentage does this observed value differ from the instantaneous value at x = 200 m?
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