MNT: clearly specify the rocket mass in utilities

Author: Gui-FernandesBR

rocketpy/utilities.py

@@ -572,7 +572,7 @@ def apogee(mass):
     source = np.array(list(zip(x, y)), dtype=np.float64)
 
     retfunc = Function(
-        source, inputs="Rocket Dry Mass (kg)", outputs="Estimated Apogee AGL (m)"
+        source, inputs="Rocket Mass without motor (kg)", outputs="Apogee AGL (m)"
     )
     if plot:
         retfunc.plot(min_mass, max_mass, points)
@@ -636,7 +636,7 @@ def liftoff_speed(mass):
     source = np.array(list(zip(x, y)), dtype=np.float64)
 
     retfunc = Function(
-        source, inputs="Rocket Dry Mass (kg)", outputs="Liftoff Speed (m/s)"
+        source, inputs="Rocket Mass without motor (kg)", outputs="Out of Rail Speed (m/s)"
     )
     if plot:
         retfunc.plot(min_mass, max_mass, points)