Date: Sat, 02 Oct 2004 19:48:28 GMT From: Johannes H Andersen <johsnospamfitter.com> Subject: Re: Town And Country Miles
Andrew Stephenson wrote: > > In article <3rdsl01oll2tuc3mm5pnaup4f05v0l98finospamcom> > mwm1(delete)nospamedu "delete" writes: > > > And, I am almost too embarrassed to ask but exactly what is a > > Newton in kilos or grams. [...] > > Not trying to tread on the other response, which gives numbers... > > IIRC, "newtons" often cause confusion in modern physics classes. > Formally, the SI unit "newton" is that force which, acting on a > mass of one kilogramme, causes it to accelerate by 1 metre/sec^2. > > Thus a lump of 1 kilo _mass_ (NB) on Earth exerts a _force_ (NB) > downward due to Earth's gravity of roughly 9.807 newtons. > > Physicists and designers of machinery prefer to be very careful > when saying words such as "kilo", "newton", "mass" and "force". > Blokes heaving on spanners here on Earth can get by with saying > that 1 newton of force == 1 kilo of force. > > (Class dismissed. No homework today.) > -- > Andrew Stephenson Yes, Newton is a measure of force. Newton meter is a measure of torque. Imagine hanging 1 Kg at the end of your arm stretched out horizontally; the torque will be (roughly) 9.807 times the arm's length (about 1 meter) times the weight (1 Kg) = 9.807 Nm. However, this calculation assumes that the are is weightless... If the arm has weight, then this contribution has to be added to the torque. This may be done by summing up torque from bits of the arm, each with a distance from the shoulder and a small weight of meat.