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9 votes
9 votes
When Andy Green broke the land speed record, his vehicle was traveling across a flat portion of the desert with a forward velocity of 341.11 m/s. How long would it take him at that velocity to travel 4.500 km?​

User Alexander Somov
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1 Answer

13 votes
13 votes

Answer:

13.192 seconds

Explanation:

You want to know the time to travel 4.500 km at a speed of 341.11 m/s.

Travel time

The relation between time, speed, and distance is ...

time = distance/speed

time = (4500 m)/(341.11 m/s) ≈ 13.192 s

It would take Andy about 13.192 seconds to travel 4.500 km.

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Additional comment

The distance of 4.500 km is rounded to the nearest meter, so may have an error of 0.5 meters. At 342.11 m/s, it takes about 1.47 ms to travel that distance. This suggests that timing to the nearest millisecond is consistent with the precision of the other numbers in the problem.

One could argue that speed is 5 significant figures, but distance is 4 significant figures. That suggests their ratio, time, is only accurate to 4 significant figures: 13.19 s. Analysis of the worst-case error in the ratio suggests that this reported value throws away some accuracy, so a better result is 13.192 s.

User Grisha Weintraub
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2.8k points