Kevin Gowen wrote:
> Ron Hitler Barrassi wrote:
> 
>>
>>
>> Ron Hitler Barrassi wrote:
>>
>>>>> If that is the case, why did you suggest using a spring based 
>>>>> device to measure the downward force 
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> Because I have heard of Hooke's Law.
>>>>
>>>
>>> But not the gravitional constant apparently.
>>>
>>>
>>>>> when the correct way to measure force is it's effect on moving *a* 
>>>>> body of mass?
>>>>
>>>>
>>>>
>>>>
>>>>
>>>> It's "effect"? I don't even know what that is supposed to mean. Who 
>>>> says that a mass acted upon by a force must be in motion? Push 
>>>> against a building as hard as you can. The building does not move, 
>>>> but you are still exerting a force upon it.
>>>
>>>
>>>
>>>
>>> F=ma
>>>
>>> (I've highlighted the definite article to draw attention to your 
>>> misreading)
>>>
>>
>>
>> I didn't elaborate on this point. You cannot use a spring to measure a 
>> force. 
> 
> 
> Really? Don't tell Hooke.
> 
>> It can only be used to measure weight (NB deliberate use of "weight", 
>> not "mass" not "force", but "weight". 
> 
> 
> Weight is a force.

Weight is a scalar. Force is a vector. You don't weigh in the 
direction of anything.  As you are in Florida your weight is in a 
different direction to mine? (I'll let you off this one)


> 
>> A spring, like your tug of war rope, requires a force at both ends to 
>> expand, or contract.
> 
> 
> Yes. In the case of a bathroom scale that measures weight with a spring, 
> the person standing on the scale provides the force at one end. The 
> floor beneath the scale provides the force at the other end.
> 

You missed the definite article again.

If a force act on a spring the spring will accelerate off in the 
direction of the force. We would lose a lot of springs that way. 
Newton's 3rd I believe.

So it is measuring two forces? More magic forces appearing from 
nowhere.