Mass on slope formula
Posted 27 January 2010 - 04:57 PM
Ok, see in a free body diagram like this (only pretend the F arrow is the pointing the opposite way, I stole it off scholar)? I know the formula is F = W sin20. But I can't figure out why, whenever I try to work it out for myself I get the F and W the other way round.
This is what I'm doing at the minute, where am I going wrong?
sinx = opposite/hypotenuse
sin20 = W/F
W = F sin20.
(PS, if you could explain it by tomorrow it'd be useful. I kind of have my prelim...)
Posted 27 January 2010 - 05:32 PM
the triangle you have to use the red coloured one, in this diagram,
W is labeled mg, on this, and F would be the bottom most line on this triangle.
Posted 27 January 2010 - 05:45 PM
Why is physics the opposite of common sense?
Posted 09 April 2010 - 03:39 PM
That is, there's a "c" in perpendicular and cos.
There is no "s" for sin in parallel, so this wee daft "c" rule is foolproof!
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