The data sheet for a small permanent-magnet dc motor provides the following parameters" Rated voltage: Vrated = 3 V, Rated output power: Prated = 0.28 W, No-load speed: nnl = 12,400 r/min, Torque constant: Km = 0.218 mV/(r/min), Stall torque: Tstall = 0.094 oz · in

a. Calculate the motor armature resistance.

b. Calculate the no-load rotational loss.

c. Assume the motor to be connected to a load such that the total shaft power (actual load plus rotational loss) is equal 0.25 W at a speed of 12,000 r/min. Assuming this load to vary as the square of the motor speed, write a MATLAB script to plot the motor speed as a function of terminal voltage for 1.0 V < Va < 3.0 V.