# Forces Involved in an Electrical Motor According to Newton's Law

1. Dec 15, 2012

### nelson_qna

Hi Everyone.

I've been trying to build an electrical motor and would like know the method to actually calculate the forces exerted on several parts in the motor according to Newton's laws. I've attached some pictures and drawings of the motor I'm trying to build. There are two scenarios that I've considered. Scenario 1 (Please see drawings Scenario 1) & Scenario 2 (Please see drawing Scenario 2)

Question 1 - "According to Drawing in Scenario 1"

Is my interpretation of all the forces involved in the motor correct according to Newton's Law? (Dismissing Friction Of Course)

Question 2 - "According to Drawing in Scenario 2"

In scenario 2 is all the forces involved in the drawing of scenario 2 correct and does it violets newton's laws?

It feels wrong as 10N is acting on the 4 bolts in the + direction and 5N is acting on the pin (Q) in the - Direction. This 2 forces should be equal according to Newton's laws. If not there will be a nett force of -5N acting on the table. I just cant see how 10N of force is transfered from the permanent magnets to point Q where the bearing pivots.

#### Attached Files:

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• ###### Scenario 2.jpg
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2. Dec 15, 2012

### zoobyshoe

Why are the magnets labeled "10N magnet" and "5N magnet". What property of the magnets is 10 and 5 Newtons?

3. Dec 15, 2012

### nelson_qna

The 10N & 5N are the forces acting against the magnet when the electromagnet is turned on.

4. Dec 16, 2012

### zoobyshoe

Maybe I'm misunderstanding your diagram but it looks like in scenario 2 you have a 10N force acting against a 5N force. According to Newton's 3rd law, this is not something that could happen in nature. Both magnets have to be experiencing the same force.