While running a marathon, a long-distance runner uses a stopwatch to time hersel

Question

While running a marathon, a long-distance runner uses a stopwatch to time herself over a distance of 100 m. She finds that she runs this distance in 19 s . Answer the following by considering ratios, without computing her velocity.

Part A

If she maintains her speed, how much time will it take her to run the next 400 m ?

Express your answer to two significant figures and include the appropriate units.

SubmitRequest Answer

Part B

How long will it take her to run a mile at this speed?

Express your answer to two significant figures and include the appropriate units.

SubmitRequest Answer

While running a marathon, a long-distance runner uses a stopwatch to time herself over a distance of 100 m. She finds that she runs this distance in 19 s . Answer the following by considering ratios, without computing her velocity.

Part A

If she maintains her speed, how much time will it take her to run the next 400 m ?

Express your answer to two significant figures and include the appropriate units.

t =

SubmitRequest Answer

Part B

How long will it take her to run a mile at this speed?

Express your answer to two significant figures and include the appropriate units.

t =

SubmitRequest Answer

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Explanation / Answer

Given in question:

d1 = 100 m

t1 = 19 s

A)

d2 = 400 m

use:

d2/t2 = d1/t1

400/t2 = 100/19

t2 = 19*4

= 76 s

Answer: 76 s

B)

d3 = 1 mile = 1609 m

use:

d3/t3 = d1/t1

1609/t3 = 100/19

t3 = 1609*19/100

= 306 s

Answer: 310 s (In 2 significant figures)

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