Question

The work of a pump is 4.2 x 106kPa cm3Kg-1. Calculate the amount of work this pump can do in KJ/Kg

Answer 1

Answer : The amount of work this pump can do in kJ/kg is,
`4.2kJkg^(-1)`

Explanation :

Conversion used :

`1kPacm^3=1000Pacm^3`

`1000Pacm^3=1000Pa* 10^(-6)m^3=10^(-3)Pam^3`

And,

`1Pam^3=1J`

So,

`10^(-3)Pam^3=10^(-3)J`

or,

`10^(-3)Pam^3kg^(-1)=10^(-3)Jkg^(-1)`

so,

`1kPacm^3kg^(-1)=10^(-3)* 10^(-3)kJkg^(-1)`

As we are given that,

work of pump =
`4.2* 10^6kPacm^3kg^(-1)`

So, the work of pump in kJ/kg is:

work of pump =
`4.2* 10^6kPacm^3kg^(-1)(10^(-3)* 10^(-3)kJkg^(-1))/(1kPacm^3kg^(-1))`

work of pump =
`4.2kJkg^(-1)`

Therefore, the amount of work this pump can do in kJ/kg is,
`4.2kJkg^(-1)`