When I do

rotation =Quantity[50.7, (("Radians")/("Seconds"))]
Torque = Quantity[15369, "Meters" "Newtons"]
PuissanceMoteur = Torque rotation
UnitConvert[PuissanceMoteur, "Watts"]

I get the error: Quantity::compat: (Meters Newtons Revolutions)/(Seconds) and Watts are incompatible units

Any explanation ?



Updating a little bit on another inconsistency:

When I do

UnitConvert[rotation, "revolutions"]*rayons[[4]] 2 \[Pi] Quantity[1, "Millimeters"]/Quantity[1, "Revolutions"]

I get:

Quantity[33943.5, ("Millimeters" "Revolutions")/("Seconds")]

However if I declare:

revs = Quantity[1, "Revolutions"]

and then do:

UnitConvert[rotation, "revolutions"]*rayons[[4]] 2 \[Pi] Quantity[1, "Millimeters"]/revs

I get:

Quantity[1, "Revolutions"]

Quantity[33943.5, ("Millimeters")/("Seconds")]

This is wrong as I do exactly the same thing here ?

  • $\begingroup$ Just found another inconsistency: $\endgroup$ Commented Apr 20, 2018 at 7:07

1 Answer 1


Apparently "Radians" is not interpreted as dimensionless by default:

UnitConvert[PuissanceMoteur, "Watts*Radians"]

779208.rad W


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