In the air, it had an average speed of 161616 \text{m/s}m/sstart text, m, slash, s, end text. In the water, it had an average speed of 333 \

Question

In the air, it had an average speed of 161616 \text{m/s}m/sstart text, m, slash, s, end text. In the water, it had an average speed of 333 \text{m/s}m/sstart text, m, slash, s, end text before hitting the seabed. The total distance from the top of the cliff to the seabed is 127127127 meters, and the stone’s entire fall took 121212 seconds. How long did the stone fall in the air and how long did it fall in the water?

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Huyền Thanh 5 years 2021-07-22T01:03:25+00:00 1 Answers 14 views 0

Answers ( )

  1. lethu
    0
    2021-07-22T01:05:09+00:00
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    Answer:

    The amount of time the stone fall in the air, t₁, is 7 seconds and

    The amount of time the stone fall in the water, t₂, is 5 seconds

    Explanation:

    Here, we have the average speed of the stone in air = 16 m/s

    The average speed of the stone in water = 3 m/s

    Total distance from top of cliff to sea bed = 127 meters

    Total time of fall = 12 seconds

    Therefore

    Let t₁ = time of the stone in air and

    t₂ = time of the stone in water

    Therefore, t₁ + t₂ = 12 s……..(1)

    16·t₁ + 3·t₂ = 127…………(2)

    From (1) t₁ = 12 – t₂

    16×(12 – t₂) + 3×t₂ = 127

    From which 13·t₂ = 65

    and t₂ = 5 seconds

    ∴ t₁ = 12 – t₂ = 12 – 5 = 7 seconds

    The amount of time the stone fall in the air is t₁ = 7 seconds and

    The amount of time the stone fall in the water is t₂ = 5 seconds.

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