Linear Momentum

Question 1

objective

Answer 1

the force on stationary targets due to water jets will be determined experimentally and compared to the force predicted theoretically using conservation of linear momentum equation

Question 2

equipment

Answer 2

water jets directed horizontally at a target, causing water jets to change direction

volume control valve

variable area rotameter mounted downstream of flow control valve measures volume flowrate in gpm

Question 3

procedure

Answer 3

attach targets (90 degree, 150 degree, 120 degree) to apparatus

open flow control valve slowly to allow trapped air to escape system

adjust control valve to obtain force readings at 1, 2, 3, 4, 5 gpm on rotameter

readings should be taken upscale and downscale

Question 4

conservation of linear momentum

Answer 4

sum of forces = (d/dt)(integral(Velocity * density * dV) + integral(Velocity * density * (Velocity dot product n) * dA)

Question 5

assumption a

Answer 5

assume that the pressure external to the jets and target is constant everywhere and equal to the ambient (atmospheric) pressure

Question 6

assumption b

Answer 6

body forces (weight) are small and can be neglected