Is it possible to convert kg/(kWh) to litres/100m ?

  • Context: Undergrad 
  • Thread starter Thread starter nb89
  • Start date Start date
  • Tags Tags
    Convert
Click For Summary
SUMMARY

The discussion centers on the impossibility of converting kg/(kWh) to litres/100m due to dimensional incompatibility. Participants highlight that kg/kWh has dimensions of time squared over length squared, while litres/meter has dimensions of length squared. Dimensional analysis confirms that conversions can only occur between units with the same dimensions, such as miles per hour to meters per second. Exceptions exist, such as using physical constants or specific systems like water heaters, where conversions may be feasible under defined conditions.

PREREQUISITES
  • Understanding of dimensional analysis
  • Familiarity with units of measurement (kg, kWh, litres)
  • Knowledge of physical constants and their applications
  • Basic principles of thermodynamics related to energy and heat transfer
NEXT STEPS
  • Research dimensional analysis techniques in physics
  • Explore the relationship between energy, mass, and specific heat
  • Learn about the conversion of energy units in thermodynamic systems
  • Investigate practical applications of physical constants in engineering
USEFUL FOR

Students and professionals in physics, engineering, and environmental science, particularly those interested in energy conversions and thermodynamic principles.

nb89
Messages
37
Reaction score
0
kg/kWhour into litres/100m? is this possible, and if so how? what happens to the hour?
 
Physics news on Phys.org
I would be more curious what happens to the kW and the meters.

Do you have a specific system in mind?

Or do you want to do the conversion by using physical constants (such as c and hbar), because then I think it is not possible (kg/kWh ~ s / m^2 while l/m ~ m^2).
 
CompuChip said:
kg/kWh ~ s / m^2 while l/m ~ m^2
Close.

What CompuChip is talking about is dimensional analysis. kg/kWh has dimensions of time2/length2, while liters/meter has dimensions of length2.

You can only convert from one form to another if both forms have the same dimensions. For example, you can convert from miles per hour to meters per second because both are in the form of length/time. There is no conversion from kg/kWh to liters/meter because the two forms are incommensurable.
 
D H explained my post very well. There are however two exceptions:
1) Physical constants are not mentioned; for example energy and mass have very different units (kg m^2 / s^2 and kg, respectively) although multiplying by the speed of light squared converts one into the other
2) There is some specific system which makes a conversion possible, for example: a water heater doing so-many kW of work will heat so many water by 1 degree (actually, this case looks a lot like 1, with the "missing" quantity being the specific heat of water which can convert Joules to degrees per kilogram, for example).
 

Similar threads

  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 2 ·
Replies
2
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 32 ·
2
Replies
32
Views
3K
  • · Replies 13 ·
Replies
13
Views
1K
  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 15 ·
Replies
15
Views
2K
  • · Replies 6 ·
Replies
6
Views
3K
  • · Replies 1 ·
Replies
1
Views
2K