JEE MAIN - Physics (2021 - 25th July Morning Shift - No. 15)
Water droplets are coming from an open tap at a particular rate. The spacing between a droplet observed at 4th second after its fall to the next droplet is 34.3 m. At what rate the droplets are coming from the tap ? (Take g = 9.8 m/s2)
3 drops / 2 sconds
2 drops / second
1 drop / second
1 drop / 7 seconds
Explanation
In 4 sec. 1st drop will travel
$$ \Rightarrow {1 \over 2}$$ $$\times$$ (9.8) $$\times$$ (4)2 = 78.4 m
$$\therefore$$ 2nd drop would have travelled
$$\Rightarrow$$ 78.4 $$-$$ 34.3 = 44.1 m.
Time for 2nd drop
$$ \Rightarrow {1 \over 2}$$(9.8)t2 = 44.1
t = 3 sec
$$\therefore$$ each drop have time gap of 1 sec
$$\therefore$$ 1 drop per sec
$$ \Rightarrow {1 \over 2}$$ $$\times$$ (9.8) $$\times$$ (4)2 = 78.4 m
$$\therefore$$ 2nd drop would have travelled
$$\Rightarrow$$ 78.4 $$-$$ 34.3 = 44.1 m.
Time for 2nd drop
$$ \Rightarrow {1 \over 2}$$(9.8)t2 = 44.1
t = 3 sec
$$\therefore$$ each drop have time gap of 1 sec
$$\therefore$$ 1 drop per sec
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