# Recent content by AryRezvani

1. ### Isotope decay, fairly simple.

The final isotope is the initial mass - 1.6. When you divide by Ao, the negative stays there, right?
2. ### Isotope decay, fairly simple.

1. Homework Statement The isotope 239Pu has a half-life of 24,100 years. After 10,000 years, a sample of the isotope is reduced 1.6 grams. What was the intial size of the same (in grams)? How large was the sample after the first 1,000 years. Round your answer to four decimal places. 2...
3. ### Evaluate the integral using the integration limits

1. Homework Statement (Between 0-3) ∫x3/√(x2+9) 3. The Attempt at a Solution I attempted U sub, but that didn't work. Neither did integration by parts; however, I do remember my teacher using a method involving sub'ing an "x" or something. Anybody? Will edit in attempts as I search...
4. ### Integration by Parts homework assistance

Hmm okay, got it. So let's say U = x2 dU = 2x dv = xe5x2 V=1/10e5x2 Then, plug into the equation, and you get.... (x2)(1/10e5x2) - ∫(1/10e5x2)2x dx EDIT: Just got it, thanks a lot for your time :).
5. ### Integration by Parts homework assistance

1. Homework Statement ∫x3e5x2 dx 2. Homework Equations uv-∫vdv 3. The Attempt at a Solution I've tried this one a few times, but keep getting answers that are just out there. Could someone, if possible, work out just the beginning.
6. ### Simple Calculus (indefinite integral)

Knocked it out, thanks guys.
7. ### Simple Calculus (indefinite integral)

1. Homework Statement Find the indefinite integral: ∫ Cos32x Sin22x dx 2. Homework Equations None required 3. The Attempt at a Solution Lost on where to start. If someone could just start me off.
8. ### Just need an answer checked on a problem

1. Homework Statement I'd like to mention beforehand this is not my work, i'm simply just trying to understand it. I believe the answer is incorrect, could someone kindly indicate why? A spherical navigation buoy is tethered to the sea floor by a vertical cable as shown in the...

Bump!
10. ### Geosychoronous Satellites and their KE/Orbitals

1. Homework Statement Prove that the product of the kinetic energy and orbital radius of a geosynchronous satellite is constant. 2. Homework Equations Not sure on the orbital radius part KE=KE = ½mGM/R 3. The Attempt at a Solution I'm lost on where to begin. How exactly would I 'prove' it?
11. ### Integrating to determine speed as a function of time

Ohh so when you integrate that you get ln(v)?
12. ### Integrating to determine speed as a function of time

Thanks for the response Tiny-Tim :) Okay, so i follow you somewhat. F = -bv (general formula for resistive force). According to Newton's second law, F=ma which can be rewritten as F=m(dv/dt). You then equate those two, and you get m(dv/dt)=-bv. What happens after this? (dv/v) is the...
13. ### Integrating to determine speed as a function of time

1. Homework Statement 2. Homework Equations The above formulas 3. The Attempt at a Solution I'm lost on where to start with this. The object has an intial velocity in the X direction and has the resistive force of the plontons acting upon it when it lands. What exactly is...
14. ### Tricky problem worth 2 points on my final grade

Re: Tricky problem worth 2 points on my final grade :) That equation was ugly as hell hahaha. Okay, the velocity of the smaller block was 1.75 m/s the larger .8 m/s
15. ### Tricky problem worth 2 points on my final grade

Re: Tricky problem worth 2 points on my final grade :) Hmm I could give it a try. In regards to KE, 1/2Mv2= 1/2mv2+1/2Mv2 Not sure how to signify a collision above. Sorry for giving you a hard time. My physics professor isn't much a professor.