Water drops fall from a tap on the floor, 5 m below, at regular intervals of time. The first drop strikes the floor when the sixth drop begins to fall. The height at which the fourth drop will be from ground, at the instant when the first drop strikes the ground is ______ m.

$(g = 10 m / s^{2})$ [2026]

Question

Water drops fall from a tap on the floor, 5 m below, at regular intervals of time. The first drop strikes the floor when the sixth drop begins to fall. The height at which the fourth drop will be from ground, at the instant when the first drop strikes the ground is ______ m.

$(g = 10 m / s^{2})$ [2026]

Smart Achievers · Accepted Answer

(4)

$Time to reach ground = \sqrt{\frac{2 h}{g}} = \sqrt{\frac{2 \times 5}{10}} = 1 sec$

$Five drops per second$

$Time between each drop = 0.2 sec$

$Time of fall for 4th drop is 1 - 0.6 = 0.4 sec$

$Height of fall of 4th drop is = \frac{1}{2} \times 10 \times {(0.4)}^{2} = 0.8 m$

$Height from ground = 5 - 0.8 = 4.2 m$

Solution

1 3.8

2 4.0

3 2.5

4 4.2

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