NTA Abhyas JEE Main2020PhysicsLaws of MotionPractice
Water coming with velocity v drops onto a mesh through which 50 % of the water passes by, 25 % loses its entire momentum and 25 % bounces back. The pressure on the mesh is
Options
- A1 2 ρ v 2
- B3 2 ρ v 2
- C3 ρ v 2
- D3 4 ρ v 2
Correct answer
D. 3 4 ρ v 2
Step-by-step solution
Mass per unit time = ρ A v Force due to momentum loss = 1 4 ρ A v × v Force due to bounce back = 1 4 ρ A v × 2 v Pressure = ρ A v 2 4 + ρ A v 2 2 A = 3 4 ρ v 2