Physics - Fluid Question with Solution | TestHub

Cross-sectional area $A=\pi r^2$, Volume of liquid flowing per second $=AV=\pi r^{2}V$ Mass of the liquid flowing out per second $=\pi r^{2}v\rho$ Initial momentum of liquid per second $=$ mass of liquid flowing $\times$ Speed of liquid $=\pi r^{2}v\rho \times v=\pi r^2{v}^2\rho$ Since the liquid does not rebound after impact, the momentum after impact is zero. $\therefore$ Rate of change of momentum $=\pi r^2{v}^2\rho$ According to Newton's second law, the force exerted on wall $=$ rate of change of momentum $=\pi r^2\rho v^2$