Question

A large tank is filled with water ( density$={10}^{3}kg/m^3$ ) . a small hole is made at a depth 10m below the water surface the range of water issuing out of the hole is R on the ground. what extra pressure applied on water surface so that the range becomes 2R ( take 1 atm$={10}^{5}Pa,g=10m/s^2$)

• A. 9 atm
• B. 4 atm
• C. 5 atm
• D. 3 atm

Answer 1

The correct option is D 3 atm

Range = velocity x time

Range will become twice, if the velocity of efflux becomes twice

$v_e=\sqrt{2gh}$

it will become twice, if h becomes 4 times, or 40m.

Thus, an extra pressure equivalent to 30m of water should be applied.

$1atm=0.76\times 13.6m$ = 10.336 m of water

$30m$ of water $\approx$ 3 atm

Hence option D is correct.