The manufacturer’s data sheet for a permanent-magnet dc motor

The manufacturer’s data sheet for a permanent-magnet dc motor indicates that it has a torque constant Km = 0.21 V/(rad/sec) and an armature resistance of 1.9O. For a constant applied armature voltage of 85 V dc, calculate
a. The no-load speed of the motor in r/min and
b. Its stall (zero-speed) current and torque (in N ?c m).
c. Plot the motor torque as a function of speed.