Force

Richard

Many thanks.

I find it easier to think and set out the result this  way if you don't mind.  This page is not public.

 1  Question

1. I want to use Dali as a sure way of replicating an activity demonstrating force
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3. the idea is to set Dali to varying numbers of lights on top
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5. keep records of distance a ball travels on a level surface
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7. I have an accurate weight scale and channel with distances marked out
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9. the ball weighs 28.6 gm
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11. a 1 light shot gives 23cm
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13. a 2 light shot gives 106cm
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15. Newton’s second law: F = ma.
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17. assuming m = 28.6gm and a = 106cm in 2 seconds how is the calculation carried out?
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19. is it the right equation?

2   More information 

1. The process was set up on our long dinner table.
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3. It is quite level.
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5. The process aims to establish the levels force from a billiard cue on a ball on a normal level billiard table.
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7. Varying from a nudge to a hard hit.
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9. Once the info is to hand, it will go public on this website.

3   Your response

1. Lets start with the equation.    F=ma.   
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3. The terms in this are
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5.      F = force, measured in Newtons
6.      m = mass, measured in kilograms
7.      a = acceleration, measured in meters per second per second.
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9. You can't use this equation in the way you are, because what you have measured is the distance the ball travels.   
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11. That "distance" is not in that particular equation at all.   
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13. And the acceleration is a very brief "push" from Dali, lasting presumably only a tiny fraction of a second.   
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15. The situation here is quite complex in fact.
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17. You say the ball travels 106cm in 2 seconds.
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19. Its unclear from what you are describing whether the ball travels that far, and then carries on travelling?    
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21. Or is it just getting 106cm, and then stopping dead?  
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23. If it stops, its because there are other forces acting on the ball - friction between the ball and surface, and air resistance.
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25. If the ball covers 106cm in 2 seconds - and is still traveling at the same speed after those 2 seconds, then we can say it reaches a constant speed of 106/2 = 53 cm/second.
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27. Similarly the 1 light shot, gives a speed of 23/2 = 11.5cm/second.
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29. Let me know what it is you are trying to calculate, and I will then be able to see if you have enough information and what the right calculation is.

4   Comment and further questions

1. 2.29 first - The process aims to establish the levels of force from a billiard cue on a ball. Varying from a nudge to a hard hit.
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3. Its unclear from what you are describing whether the ball travels that far, and then carries on travelling?    3.19
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5. Or is it just getting 106cm, and then stopping dead?  3.20
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7. Answer is the latter 
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9. Don't understand -  your 3.11  That "distance" is not in that particular equation at all.   

Look forward to the next stage.