5. [20] A DC permanent magnet motor develops 35.3 in-lbf of torque when operated at an armature voltage of Va-60 volts and a speed of 1433 RPM. The manufacturer claims

that the motor has a no-load speed of 3344 rpm when operated at 60 V. Determine: a) the motor's theoretical "no-load" speed,WNL, b) the motor's theoretical back-EMF constant, ka, c) the motor's theoretical torque constant, ka,d) the motor's theoretical resistance, Ra,e) the motor's efficiency at 1433 RPM when operated at an armature voltage of Va-30 volts.