Gerhard Fiedler wrote:

> RussellMc wrote:
>=20
>>> Agreed. Many an exam question was corrected by me during an exam by
>>> checking the units and finding something amis. VERY useful sanity check=
..
>>=20
>> As long as one has the courage of one's units.
>=20
> They usually make actually sense, if you think of it.
>=20
>> eg
>> The unit of effectiveness of a rocket fuel is (arguably) seconds.
>> (thrust.seconds per mass of fuel).
>=20
> Isn't thrust a force? If so: Ns/kg =3D kg m^2 s^-3 * s / kg =3D m^2 s^-2 =
??

Oops... brain fart :)=20

Ns/kg =3D kg m s^-2 * s / kg =3D m/s, which probably can be interpreted as
the final velocity to which a unit of mass can accelerate something (no
gravity, no friction, etc.)

>> The unit of fuel consumption of a vehicle is area (ie length^2 =3D
>> m^2)(more usually expressed here as l/100km)
>=20
> That's the (vertical) area of the fuel strip that the vehicle consumes
> while driving, so to speak. 10l/100km =3D 10e-3/100e3 m^2 =3D 0.1e-6 m^2 =
=3D
> 0.1 mm^2
>=20
> Gerhard
--=20
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