What does the Dynamometer show?

  • Thread starter Fishingaxe
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  • #1
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Homework Statement



What does this dynamometer show?

http://imageshack.us/photo/my-images/826/0uqz.png/

That's pretty much the entire problem, I realize that this is utterly pathetic to post here but I lack the very foundations in physics and after googling this "problem" I still haven't gotten any results, I've thought about it as well and I've only come to one conclusion:

Homework Equations





The Attempt at a Solution


My conlusion is that it has a weight of 3kg pulling it down, that's it. I know it's stupid to say that it's my conclusion after hours of googling and thinking about it, and I probably come across as a retard and rightly so. If this is such a simple problem and doesn't deserve to be posted here then I apologize. I figured if I'm having problem with a "problem" why not ask the geniuses?

PS: I tried to upload the picture using the insert photo feature but somehow it came out blank so I decided to use insert link.

Homework Statement





Homework Equations





The Attempt at a Solution

 

Answers and Replies

  • #2
NascentOxygen
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What does this dynamometer show?

http://imageshack.us/photo/my-images/826/0uqz.png/

Hi Fishingaxe, [Broken]

I don't see a dynomometer. To me that looks like a spring balance for measuring a force (or a weight).

"Why not ask the geniuses?" indeed! :smile: But while waiting for them to answer, why not search via google for a physics equation that relates weight to mass. :wink:
 
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  • #3
It measures a force in dynes, the unit of force in the cgs (in which measurements are made in centimeters, grams and seconds units) system. 1 dyne is a force of 1 gram cm/s2. In the S.I. unit of measurement the unit of force is newtons which is 1 kg m/s2.

100 000 dyne = 1 newton
 
  • #4
CWatters
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From Wikipedia..

"A dynamometer or "dyno" for short, is a device for measuring force, moment of force (torque), or power."

So fishingaxe will need to tell us what his dynamometer is designed to measure (force, torque or power).

Force is usually measured in Newtons
Torque in Newton Meters
Power in Watts.

or related units.
 
  • #5
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It measures a force in dynes, the unit of force in the cgs (in which measurements are made in centimeters, grams and seconds units) system. 1 dyne is a force of 1 gram cm/s2. In the S.I. unit of measurement the unit of force is newtons which is 1 kg m/s2.

100 000 dyne = 1 newton


Thank you very much for your answer, so if I understand this correctly the solution is as follows:

1 dyne = 1 gram cm/s2

The weight is 3kgs which is 3000 grams and that is 3000 dynes so that should be 0.03N? Since 100.000 dyne = 1N.

Or is 1N = 1kg m/s2 so the force is 3N?

I am sorry about still being confused.
 
  • #6
86
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From Wikipedia..

"A dynamometer or "dyno" for short, is a device for measuring force, moment of force (torque), or power."

So fishingaxe will need to tell us what his dynamometer is designed to measure (force, torque or power).

Force is usually measured in Newtons
Torque in Newton Meters
Power in Watts.

or related units.

Hello, I believe it is in Newtons, I study from my home and the assignment I simply downloaded from the schools website, and I have as much information as you got from me. However from overlooking the other physic problems I have I believe it is supposed to be solved in N.
 
  • #8
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If the scale measures force and reads in Newtons then use

F = mass * acceleration

where the mass "m" is 3kg and the acceleration "a" = g = 9.81m/s2 (sometimes 10 m/s2 is used as an approximation).

Example Dynamometer here has a scale marked in Newtons..

http://www.alibaba.com/product-gs/287398142/TRANSPRENT_DYNAMOMETER.html

Now I think I got it, thank you.

Solution: F = mass * acceleration. F = 3kg * 9.81m/s2 = 29.43 N.

F = 29.43 N.

Is this correct?
 
  • #9
Yes, so the dynamometer will read 29.43 x 105 dynes.
you should actually round this off to one significant digit since the problem only gives 1 significant digit - 3 kg.
 
  • #10
NascentOxygen
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Science Advisor
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Now I think I got it, thank you.

Solution: F = mass * acceleration. F = 3kg * 9.81m/s2 = 29.43 N.

F = 29.43 N.
Well done sorting that out! :smile:
 

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