You are characterizing a motor with zero friction.  You power the motor with the nominal voltage of 10 V and find that it spins at 100 rad/s with no load.  The resistance of the motor is 2 ohms.  The motor coils can dissipate 1 watt without overheating.  

1.  Calculate the following in the SI units indicated:
(a) motor constant (Nm/A):  10/100 = 0.1 Vs = 0.1 Nm/A
(b) stall current (A):  10/2 = 5 A
(c) stall torque (Nm):  5*0.1 = 0.5 Nm
(d) maximum continuous current (A):  I^2*R = 1 watt (overheating), I = sqrt(0.5) A
(e) nominal speed (speed at max continuous current) (rad/s):  10 = kw + IR, w = (10-IR)/0.1 = (10-2*sqrt(0.5))/0.1 = 85.9 rad/s
(f) maximum mechanical power output (W): (1/4)*tstall*I0 = (1/4)*0.5*100 = 12.5 W
(g) efficiency at maximum mechanical power (%):  at 1/2*tstall, current is I = 2.5 A, so power in = IV = 25 W.  Efficiency is 12.5/25 = 50%.

2.  Draw the speed-torque curve, indicating the maximum speed and torque.

x-axis is torque, y-axis is speed, and curve is a straight line from (torque = 0, speed = 100 rad/s) to (torque = 0.5 Nm, speed = 0 rad/s).