The magnetization curve taken at 1000 r/min on a 200-V dc series motor has the following data:
The armature-circuit resistance is 0.25 Ω and the series-field resistance is 0.25 ?4. Calculate the speed of the motor
(a) when the armature current is 25 A, and
(b) when the electromagnetic torque is 36 N · m. Neglect the armature reaction.