Electric Motors (DC)?

Question

hey i have four questions for yas most apprieciated if you can help!!!
Question 1
Where does the energy that makes the DC electric motor work originally come from?

Question 2
What difficulties would you have measuring the current flowing through a DC electric motor when it is operating?

Question 3
Please Explain how you would calculate the resistance (in ohms) of a DC electric motor circuit.

Question 4
PLease name as many appliances that have electric motors in them

please and thank-you if ya answered!!! PEACE OUT :D

Answer 1

1. Probably a battery, maybe a rectifier. 99% of the energy on earth comes from the sun.

2. To measure directly, all the current through the motor would have to go through the meter. For a large motor, this could be dangerous. A 'bridge' would send a known *part* of the current through the meter, from which one could deduce the full current. For a smaller motor, it could be hard to disconnect and put the meter into the circuit.

3. Measure voltage across motor. Use R = E/I, (ohm's law),
where E is the voltage and I is the current.

4. Most drills, refrigerators, mixers, food processors, air conditioners, fans, and computers.