Question

A mass of 7 kg undergoes a process during which there is heat transler frorn the mass at a rate of 2 kJ per kg, an elevation decrease of 40 m, and an increase in velocity from 13 m/s to 23 m/s. The specific internal energy decreases by 4 kJ/kg and the acceleration of gravity is constant at 9.7 m/s2. Determine the work for the process, in k.J

Answer 1

Answer:44.61 KJ

Step-by-step explanation:

Let h_1,V_1,Z_1 be the initial specific enthalpy,velocity&elevation of the system

and h_2,V_2,Z_2 be the Final specific enthalpy,velocity&elevation of the system

mass(m)=7kg

Applying Steady Flow Energy Equation

`m\left [ h_1+(v_1^2)/(2g)+gZ_1\right ]`+Q=
`\left [ h_2+(v_2^2)/(2g)+gZ_2\right ]`+W

`h_1-h_2=4 KJ/kg`

`V_1=13m/s`

`V_2=23m/s`

`Z_1-Z_2=40m`

substituting values

`7\left [ h_1+(13^(2))/(2g)+gZ_1\right ]+7*2` =
`\left [ h_2+(23^2)/(2g)+gZ_2\right ]`+W

W=
`7\left [h_1-h_2+(V_1^2-V_2^2)/(2000g)+g(\left (Z_1-Z_2 \right ))/(1000)\right ]`+Q

W=
`7\left [4+(13^2-23^2)/(2000g)+g(\left (40 \right ))/(1000)[\right ]`+
`2* 7`

W=44.61KJ