In a $100$ meter track event, Alice runs at a constant speed and crosses the finish line $5$ seconds before Beatrice does. If it took Beatrice $25$ seconds to complete the race, how many seconds would it take Alice to run $50$ meters?

Question

Physics

Adrian Long

26 March, 08:52

In a $100$ meter track event, Alice runs at a constant speed and crosses the finish line $5$ seconds before Beatrice does. If it took Beatrice $25$ seconds to complete the race, how many seconds would it take Alice to run $50$ meters?

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Answers (1)

Know the Answer?

Faith Kim · Answer 1

10s

Explanation:

If it took Beatrice 25 seconds to complete the race

Distance = 100 meter

Beatrice speed = 100/25

= 4m/s

If Alice runs at a constant speed and crosses the finish line $5$ seconds, she must have completed the race in 20s (25 - 5).

Her speed where constant

= 100/20

= 5 m/s

It would take Alice

= 50/5

= 10s

It would take Alice 10s to run $50$ meters.