3. Daniel stands on a bridge over a river. He drops a coin and notes that the coin takes 3 s to reach the river below. He must b

Question

3. Daniel stands on a bridge over a river. He drops a coin and notes that the coin takes 3 s to reach the river below.

He must be standing

above the river.

A 10 m

B. 15 m

C. 30 m

D. 45 m

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Yến Oanh 2 months 2021-07-30T03:08:10+00:00 1 Answers 4 views 0

Answers ( )

    0
    2021-07-30T03:09:47+00:00

    Answer:

    45 m

    Explanation:

    Initial velocity of the coin = 0 m/s  (since he dropped it from his hands)

    time spent in falling – 3 sec

    distance s = ?

    using

    s = ut + \frac{1}{2}gt^{2}

    where

    s is the distance the stone fell

    u is the initial velocity

    t is the time spent falling

    g is acceleration due to gravity = 10 m/s^2 (positive downwards)

    substituting values, we have

    s = (0 x 3) +  \frac{1}{2}(10 x 3^{2})

    s = 45 m

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