The great limestone caverns were formed by dripping water. The acceleration of gravity is 9.81 m/s 2 . If water droplets of 0.26 mL fall from a height of 9 m at a rate of 15 per minute, what is the average force exerted on the limestone floor by the droplets of water during a 7 min period? Answer in units of N.

Respuesta :

Explanation:

In order to calculate the average force exerted we need to calculate the mass of water droplet first of all as follows.

       Volume = [tex]0.26 ml \times \frac{1 \times 10^{-6} m^{3}}{1 mL}[/tex]

                     = [tex]2.6 \times 10^{-7} m^{3}[/tex]

As we know that density of water is 1000 [tex]kg/m^{3}[/tex]. The mass is given as follows.

              m = [tex]\rho V[/tex]

                  = [tex]1000 kg/m^{3} \times 2.6 \times 10^{-7} m^{3}[/tex]

                  = [tex]2.6 \times 10^{-4} kg[/tex]

As the given water droplet falls from a height of 9 m. Therefore, its velocity when it hits the ground is as follows.

                     v = [tex]\sqrt{2gh}[/tex]

                        = [tex]\sqrt{2 \times 9.8 m/s^{2} \times 9}[/tex] m/sec

                         = 13.28 m/sec

Now, we will calculate the rate of droplet fall as follows.

                R = [tex]\frac{15}{1 min} \times \frac{1 min}{60 sec}[/tex]

                    = 0.25 drops/sec

Therefore, force will be calculated as follows.

               F = [tex]R \frac{\Delta p}{\Delta t}[/tex]      ([tex]\Delta p = m \times v[/tex])

                  = [tex]0.25 drops/sec \times \frac{2.6 \times 10^{-4} kg \times 13.28 m/sec}{1}[/tex]

                  = 8.632 N

Thus, we can conclude that 8.632 N is the average force exerted on the limestone floor by the droplets of water during a 7 min period.