Recent content by desquee

You were right Hornbein. I just tried measured the greatest likely error of a scoop. I measured the weight of exactly 1/3 cup of feed (or as exact as I could make it given that the feed was solid). Then I took a scoop as overflowing as it could be without feed falling out, removed the excess...

My original assumption is that the error for each scoop was 10%, from which the 0.34% for 850 scoops was calculated. Was that 1% a typo and you meant to say that you bet the tendency is greater than 10%?

Hornbein: What sort of systemic errors should I be looking for? The feeding method was: fill scoop from feed bucket, pour feed from scoop into feeding container in cage, count the number of scoops I added. And the number I'm interested in is the total amount of feed I gave to the rabbits (so...

OK, so reading that, it looks like the equation given by mathman is for the std of the mean of the sample. But what I'm trying to figure out is the std of the sum of the sample, and I don't see that the link explains how to do that.

Thanks mathman. That comes to 0.34%. I want to better understand how that equation is derived, do you by any chance have a link to an explanation?

(Sorry if this is the wrong place for this question, I wasn't sure where to put it) I've been running an experiment with rabbits, and am trying to figure out the error of my feed measurement. I fed them using a 1/3 cup measure, and recorded the number of scoops they got. I estimated that the...

You could break down each force into its x,y,z components, at which point the same strategies of composing forces in 2-d will apply.

Yes, it's very odd. The heating and cooling strains would have had to pull at least 3 specific things apart in the wiring. And since I can still see the wires through the semi-transparent resin, it would have to pull it apart in a subtle enough way so as not to be visibly obvious.

Thanks for the suggestions. My meter's test out fine on other circuits. I checked the terminals (they're cast together with the wires), and they conduct across themselves fine, so there's no resin on them. I tried connecting pairs of terminals to a battery and a load, but there was no...

I've been building a 3 phase delta wired alternator. I recently cast the stator in fiberglass resin, and now i get no response from the terminals. Before casting, I used the multimeter's resistance setting to test the connections between each pair of the three terminals, and all registered a...

You're right Sammy, they are the same. I expanded each answer and got (1/24)*(e3x+e-3x+3ex+3e-x) for both. I must have made some input mistake when I plugged in a number for x. Thanks!

Solving this the simple way I got the right solution, but I also tried to solve it a different way and got it wrong. I want to know where I went wrong the second way. 1. Homework Statement ∫cosh2(x)sinh(x)dx = ? Homework Equations cosh(x)sinh(x) = (1/2)*sinh(2x) The Attempt at a Solution The...

Got it, Thanks.

Yup. I see that y' is the rate of change of the fraction, but I'm still not sure why why it equals what it does.

This was given as a problem in a calculus textbook I'm working through (apologies if this should have gone in the physics forum) 1. Homework Statement An ant crawls at 1foot/second along a rubber band whose original length is 2 feet. The band is being stretched at 1 foot/second by pulling the...