Recent content by jrd007

Can anyone explain to me, using Dalton's Law, why a fresh cup of tead made with boiling water is not as hot at higher altitudes as it is at sea level? I know the law is: the law that the total pressure exerted by a mixture of gases is equal to the sum of the partial pressures of the gases...

I mis typed it the first time.

Opps. I mean kg! :-S

(also so you cannot use L = Lo x sqroot(1-v^2/c^2)?) Look below. could you also have said --> 85 = 35 x sqroot(1-v^2/c^2) and then solve for V?

Btw, my book doe snot use 4 pie. So I solve for E by : E = h/900 s = =1.06 x 10^-34 J/900 s? = 1.2 x 10^-37 J Then I use E = mc^2 1.2 x 10^-37 J = m(3.0 x 10^8)^2 m = 1.54 x 10^-54 m Is that correct! =)

Yes I know E = mc^2, but I still lost as to how to solve for uncertainty...

So I did it incorrectly? I am getting a bit confused...

I think I know how to do this problem, but need to make sure... so... 1) In an Earth reference frame, a star is 82 light years away. How fast would you have to travel so that to you the distance would only be 35 light years? First I have two simple questions: 1. Light years is in a unit...

Yes, that would be: (delta p)(delta x) > h or (energy)(time) > h... So how does that help? All I know is a time = 900 s. So am I solving for energy? e =(1.06 x 10^-34 J)/(900 s) = 1.2 x 10^-37 J ? ? ?

Okay... still do not see an equation. It is from our chapter on Quantum Mechanic of Atoms.

This is a really simple problem, but I cannot seem to find the equation. Any help? Thank you. 1) A free neutron has a mean life of 900 s. What is the uncertainty in its mass?

Now I see. You actually manipulated the equation wrong. The Area of T is equal to AcPt/Pc. That gives the correct answer. Thanks for a good try though. Does number two look okay?

That does stil not work. Area of copper will be 4.91 mm^2. If you then use. A_T = \frac {\rho_C } { \rho_T A_C } You get Area of T = .0611 and then if we use the equation of a circle for this area we get d = .27 mm.

I did all the word but my answers are not matching my books? 1) Can a 2.5 mm-diameter copper wire have the same resistence as a tungsten wire of the same length? Give numerical detials. Answer, yes, 4.6 mm Here is what I did: ( p = resistivity ) R = p(L/A) so I set R(Cu) = R(tug) and...

Can anyone answer me a curious question. Why are electric field lines perpendicular to equipotential lines? Is it because force and charge are inversly proportional or is there a more simple reason? Thanks.