Water flows through a horizontal coil heated from the outside by high temperature flue gases. as it passes through the coil water changes state from liquid at 200 kpa and 80 c to vapor at 100 kpa and 125 c. its entering velocity is 3 m s-1 and its exit velocity is 200 m s-1. determine the heat transferred through the coil per unit mass of water. enthalpies of the inlet and outlet streams are 334.9 and 2,726.5 kj kg-1, respectively.

For the steady flow process, the first law is written like

 DH + Du2/2 + gDz = Q + Ws

 since there is no shaft work, Ws = 0

 and flow is horizontal, Dz = 0

 Therefore,

 DH + Du2/2 = Q

 substituting for the quantities,

 (2726.5 - 334.9) x 1000 + (200^2 - 3^2)/2 = Q (in terms of J/kg)

 Q = 2411.1 kJ/kg

 Heat transferred through the coil per unit mass of water = 2411.1 kJ

root word, prefixes, and suffixes

force is based upon mass and acceleration.the statement is not always true.

it can be explained from newton's second law of motion.

as per newton's second law of motion the rate of change of momentum is directly proportional to the applied force and takes place along the direction of force.

mathematically it can be written as -

                                              ⇒      

here   k is the proportionality constant whose value is 1.

                                                            [a is the acceleration=dv/dt]

hence we see that force not only depends on mass and acceleration but also on velocity and rate of change of mass. force f will depend on mass and acceleration only when mass is constant.

hence the statement that force is based upon mass and acceleration is false.