Blossom'sGirl Posted December 7, 2011 Share Posted December 7, 2011 This is a question copied directly out of the CPO Physical Science book using ohm's law I=V/R I get .75 ohms not 3 ohms. Am I missing something. (I hate studying electricity, that is why I went into mechanical engineering) b. A motor in a toy car needs 2 amps of current to work properly. If the car runs on four 1.5-volt batteries, what is the motor’s resistance? Answer: 3 ohms You can look at the book here: We are in the Physical science book, Unit 4, p.200 http://alms.hermiston.k12.or.us/science-text-books Quote Link to comment Share on other sites More sharing options...
Bambam Posted December 7, 2011 Share Posted December 7, 2011 This is a question copied directly out of the CPO Physical Science book using ohm's law I=V/R I get .75 ohms not 3 ohms. Am I missing something. (I hate studying electricity' date=' that is why I went into mechanical engineering) b. A motor in a toy car needs 2 amps of current to work properly. If the car runs on four 1.5-volt batteries, what is the motor’s resistance? Answer: 3 ohms [/quote'] I = 2 amps V = 1.5 + 1.5 + 1.5 + 1.5 (four 1.5 V batteries in series, right?) I= V / R 2 = 6 / R R = 3 ohms I never enjoyed the mechanical engineering classes I had to take which is why I majored in Electrical Engineering! Quote Link to comment Share on other sites More sharing options...
Blossom'sGirl Posted December 8, 2011 Author Share Posted December 8, 2011 Oh duh! I totally missed the four batteries. That's what I get for trying to multi-task during science class. I guess I have to remember that when I get on the kids' cases for not reading the problem carefully. Thanks! Quote Link to comment Share on other sites More sharing options...
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