Question

Fire is caught at height of 125 m from the fire brigade. To extinguish the fire, water is coming out from the pipe of cross section 6.4 cm with rate 950 litre/min. Find out minumum velocity of water exiting from fire brigade tank(g=10m/s^2) (1) 5 m/s (2) 10 m/s (3) 25 m/s (4) 50 m/s

Answer 1

Rate of flow=A*v=same everywhere in pipe;v=950*10-3 m3/60s*(1/(pi*3.2*10-2)^2); v=5 m/s;

Answer 2

Answer:

The minimum velocity of water exiting from fire bridge is 50 m/s.

(4) is correct option.

Explanation:

Given that,

Height = 125 m

Flow rate = 950 litre/min

Cross section of pipe = 6.4 cm

We need to calculate the minimum velocity of water exiting from fire bridge

Using equation of motion

$v^2=u^2+2ah$

$v=\sqrt{2gh}$

Put the value in the equation

$v=\sqrt{2\times10\times125}$

$v=50\ m/s$

Hence, The minimum velocity of water exiting from fire bridge is 50 m/s.