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pls help with basic physics

v = 10 +/- 1
d = 13 +/- 0.5
do d/v = 1.3 +/- 0.18
why is the error 0.18?

thanks
(edited 6 years ago)
Reply 1
Avatar for Bobeth
Bobeth
8
It should be +/- 0.18 not 1.8
Reply 2
Avatar for user6172
user6172
OP
5
Original post by Bobeth
It should be +/- 0.18 not 1.8


oh right sorry i copied it down wrong. but why is it that?
Reply 3
Avatar for Bobeth
Bobeth
8
Original post by user6172
oh right sorry i copied it down wrong. but why is it that?


You have to convert them to percentage uncertainties. You can't directly get the uncertainty of d/v using the absolute uncertainties of v and d ( which are +/- 1 and +/- 0.5). When you multiply or divide values, to get the uncertainty you have to ADD the two % uncertainties. Then you have to convert it back to an absolute uncertainty.

% uncertainty is ((absolute uncertainty)/given value)) x100
(edited 6 years ago)
Reply 4
Avatar for user6172
user6172
OP
5
Original post by Bobeth
You have to convert them to percentage uncertainties. You can't directly get the uncertainty of d/v using the absolute uncertainties of v and d ( which are +/- 1 and +/- 0.5). When you multiply or divide values, to get the uncertainty you have to ADD the two % uncertainties. Then you have to convert it back to an absolute uncertainty.

% uncertainty is ((absolute uncertainty)/given value)) x100


Thanks
wait, how do you actually do the calculation. im stuck.
never mind. just got it

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