A cycle track is 500 metres long. Amy completes 10 laps. She travelled at an average speed of 12.5 metres per second. She puts one fast lap completing it in 35 seconds. What was the average speed for the first 9 laps?

Question

Physics

Gael

2 November, 15:22

A cycle track is 500 metres long. Amy completes 10 laps. She travelled at an average speed of 12.5 metres per second. She puts one fast lap completing it in 35 seconds. What was the average speed for the first 9 laps?

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Answers (1)

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Lincoln Cochran · Answer 1

The fast lap is irrelevant to the question, because it didn't happen

until after the 9 laps that you're interested in.

To be perfectly technical about it, we don't actually have enough

information to answer the question. You told us her average speed

for 10 laps, but we don't know anything about how her speed may

have changed during the whole 10 laps. For all we know, maybe

she took a nap first, and then got up and drove 10 laps at the speed

of 125 metres per second. That would produce the average speed

of 12.5 metres per second and we would never know it Why not?

That's only 280 miles per hour. Bikes can do that, can't they?

IF we can assume that Amy maintained a totally steady pace through

the entire 10 laps, then we could say that her average for 9 laps was

also 12.5 metres per second.