# Search results

1. ### T-butyl vs. isopropyl subsitutions

Homework Statement T-butyl chloride can undergo substitution reaction to create C4H9OH, but isopropyl chloride cannot. Why is this? Homework Equations The Attempt at a Solution I'm guessing it has to do with the extra carbon. Maybe since it is a secondary halide, the substitution...
2. ### Substance decrease by factor of 100? (radioactivity)

Yes, I just forgot to put it in. Thanks for your help :)
3. ### Principal Quantum number by size?

Alrighty, thank you very much :)
4. ### Substance decrease by factor of 100? (radioactivity)

Ok I think I got it: N(o)/100 = N(o)e-kt 1/100 = e-kt ln(1/100) = e-kt ln(1/100) = -[(ln2)/8](t) 53.1 days = t
5. ### Principal Quantum number by size?

So I'm right? The answer is just 97? I thought the principal quantum numbers (n) only go up to like 5 or 6 or something like that though.
6. ### Substance decrease by factor of 100? (radioactivity)

Homework Statement Radioactive iodine (131-I) has a half life of 8 days. How long does it take for iodine to be reduced by factor of 100? Homework Equations N(t)=N(o)e-kt k=ln100/t1/2 The Attempt at a Solution N(t)=N(o)e-kt N(t)/N(o)=e-ln(100/8)t Now I'm stuck. I would...
7. ### Principal Quantum number by size?

Homework Statement What is the value of the principal quantum number for a hydrogen atom to have a size of one micron? Homework Equations r=(5.3x10-11)(n2) r=1x10-6/2=5x10-7 The Attempt at a Solution 5x10-7=(5.3x10-11)(n2) 97.1 = n How is this possible? lol Maybe it's more complicated...
8. ### Charge on each mass?

Alrighty, thanks a lot :)
9. ### Charge on each mass?

Well I don't know what to do then lol.
10. ### What is electric field problem?

So then the final answer is 3.6Coulombs?
11. ### What is electric field problem?

I posted it above ^ you didn't say if its correct or not lol.
12. ### What is electric field problem?

Don't you divide 2mm by 100 twice to get to m? Yes, A is 0.36m. They give the dimensions of the plates as .6mx.6m Yup, that's what they give in the question. It says charge density is 10 Coulombs/m2
13. ### Charge on each mass?

Nope, I double-checked the problem and I wrote it exactly the same. Is it possible we can used substitution? Ex, solve for q and then plug it back into solve for r.
14. ### What is electric field problem?

Ooooooh I see, thanks, you made that really clear. So, E = (1.13 x 1011)(10) = 1.13x1012 Coulombs/m2 b) V = EL = (1.13x1012)(.0002m) = 2.26x108Volts c) I'm going to attempt this one and say that since you said E = (1.13 x 1011)(Q/A), then: 1.13x1012=(1.13x1011)(Q/.36) 27.8...
15. ### What is electric field problem?

a) Well it gives 10 Coulombs/m2 which equals Q/A, so how do I relate this to E=1.13x1011 Q/A? b) V=(answer in A)(.00002m) c) I still don't quite understand
16. ### Charge on each mass?

Alright so let me attempt this: F=mg=(1)(9.8)=9.8. This can then be used: F=Kq1q2/r2 9.8=(9x109)(q1q2)/r2, but then I'm still confused with what r is. Is it what I said?
17. ### What is electric field problem?

Homework Statement Two uniform plates have a uniform charge density of 10 Coulombs/m2. The plates have dimensions of 0.6x0.6 m2 and are separated by 2mm a) The electric field (V/m) between the two plates is given by E=1.13x1011 Q/A where Q is the charge in Coulombs on one plate and A is the...
18. ### Charge on each mass?

I believe r in the first equation is between the centr of the Earth and the object, so would it just be as if the object is on the surface of the earth. And the 2nd equation is the distance between the two objects.
19. ### Charge on each mass?

Homework Statement Two equally charged 1g masses repel each other. The lower mass is held fixed. a)What is the charge on each mass for the Coulomb force to balance the gravitational force of the Earth on the upper mass? b)How many elecetrons does this rep? Homework Equations...
20. ### What are the resonant wavelengths?

I don't believe we did, but if you say that it wouldn't make sense if we didn't, then why would we be assigned this question? And it says that L=5 in part b.
21. ### What are the resonant wavelengths?

We are just touching on basics of different waves, sound included. Yes we did touch a little on the nodes. No, we did not discuss tuning forks in a pipe.
22. ### What are the resonant wavelengths?

Homework Statement Consider pipe of length L. The pipe is closed at one end and open at the other allowing a standing wave where a node exists at the closed end and a max exists at the open end. a) what are the resonant wavelengths? b) If L=5, what is the lowest frequency? Homework...
23. ### How long should she wait?

Alright, thanks a lot :D
24. ### How long should she wait?

So basically it has nothing to do with any wave equations? Its more of a kinematics question? So light would be: 3x108=33/t t=33/3x108 t=1.1x107 So you would just add the two and it would basically be 0.1sec that the violinist should wait since t is so small for light? b) They see the...

Frequency?
26. ### How long should she wait?

Would I use the equation speed of light=(frequency)(wavelength) and then solve for frequency? Speed of light = 3x108 and wavelength = 33m?
27. ### How long should she wait?

Homework Statement An orchestra wants to have a listener in front of a conductor hear notes at the same time, played by the violinist located next to the conductor and from a drummer located 33m further back. a) How long should the violinist wait before playing her note? (assuming drummer...
28. ### Another Momentum one, sorry

Alright I got it, thanks a lot :D
29. ### Another Momentum one, sorry

Would the vertical component be the same as the first equation except we would use sin60 instead of cos60?
30. ### Another Momentum one, sorry

ok i think i got it, hopefully lol: p=mv m1u1+m2u2=m1v1+m2v2cos60 (.5)(2)+(1)(0)=.5v1+(1)(.75)cos60 1=.5v1+.375 .625=.5v1 1.25=v1 b) The final direction would just be forward because the value of the speed is positive. Or do you use a formula to find the direction. I'm...
31. ### Another Momentum one, sorry

Would the angle be 90 degrees which would make the whole thing 0? I just don't know how to do it singly lol. Alright I'll work on this
32. ### Another Momentum one, sorry

Well I've been working on this question and this is what I came up with. Please take the time to read it and give your input. Thank you very much :):) m1=.5kg m2=1kg v1I=2 m/sec v2I=0 m/sec v2F=.75 m/sec P=mvcos =(1)(.75) =.75 kgm/sec PTotal=m1v1I+m2v2I PTotal=m1v1F+m2v2F PTotal=(m1+m2)v...
33. ### Another Momentum one, sorry

Homework Statement A .5kg hockey puck moving at 2 m/sec strikes another puck with a mass of 1kg. The puck then travels at an angle of 60 degrees with a speed of .75m/sec with respect to the motion of the original puck. a) What is the final speed of the first puck? b) What is the final...
34. ### Vectors and Angles

Follow the outline they give you.
35. ### Kinetic E & Potential E Question

Okay I think I got it. Thank you :D :D
36. ### Kinetic E & Potential E Question

Would this work? I find change in KE which then can be used in the equation -KE=PE?
37. ### Kinetic E & Potential E Question

How would you find out the height difference to find the potential energy difference?
38. ### Kinetic E & Potential E Question

So let's say, initial speed = 55 and final = 25. These would be the only differences in KE1,KE2?
39. ### Kinetic E & Potential E Question

Yes my bad. and for c, does it look something like this?: mgh=mv2/2 The m's cancel and you get: gh=v2/2 Solving for h, h=v2/2g And then you could work out W=mgh?
40. ### Kinetic E & Potential E Question

ok I think I know, v2=v1 -at 0=55-(9.8)(4.5) Is this correct? And how about c? you didn't comment on that
41. ### Kinetic E & Potential E Question

Homework Statement A 55kg mass is projected vertically with and initial speed of 30m/sec a) what is original kinetic energy b) What is kinetic E after 4.5 seconds c) What is chg in gravitational potential E in these 4.5seconds? Homework Equations W=mv2/2 W=(m/2)(gt)2 W=mgh...
42. ### Niagra Falls Q

Alright niceee thanks for the help :)
43. ### Niagra Falls Q

Homework Statement Estimate E generated by water falling over Niagara falls in 5 day. Height = 150m Water flow =104m3/sec t=5x24x60x60=4320000sec Homework Equations P=W/t mgh=mv2/2 The Attempt at a Solution Work=mgh=m(9.8)(150) Time=432000seconds P=m(1470)/4320000 I just...
44. ### What does this tell you about how the moons were created?

So the radius IS 2x larger
45. ### What does this tell you about how the moons were created?

Then where does the factor of 2 come in?? lol
46. ### What does this tell you about how the moons were created?

One would be r13=kM1 and the other would be 2r23=kM2 which is r23=kM2/2
47. ### What does this tell you about how the moons were created?

One would be r3=M and the other would be 2r3=M which is r3=M/2
48. ### What does this tell you about how the moons were created?

So one moon would just be half the mass?
49. ### What does this tell you about how the moons were created?

Not really lol. I was thinking more along the lines of r3=M and then cubed root M to find the radius. The T can be ignored since its a constant and is the same for both moons.
50. ### What does this tell you about how the moons were created?

Ok, this is what I thought of first. When you cross multiply the T (which is constant) multiplies with M so you get M. Then you divide M by 2 and then cube root the answer and you get a smaller answer. But then I used common sense and thought that shouldnt the mass be larger if the radius is...