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• Users: Sam
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1. ### Finding Inflection Points (Applied Calc Question)

The problem: Find the inflection points, if any, for the following: f(x) = e^x + x^-1 I know to find inflection points I have to: 1. Compute f''(x) 2. Determine the points in the domain of f for which f''(x) = 0 or f''(x) does not exist 3. Determine the sign of f''(x) to the left...
2. ### Displacement - What am I doing wrong?

I figured it out... -14*cos(13.2355042*.4) = -7.69 Thanks.
3. ### Displacement - What am I doing wrong?

Still isn't coming out I then came up with -13.29355 m That is still incorrect. Sorry... frustrated.
4. ### Displacement - What am I doing wrong?

Problem: a 0.28 kg mass is suspended on a spring which stretches a distance of 5.6 cm. The mass is then pulled down an additional distance of 14 cm and released. What is the displacement from the equilibrium position with the mass attached (in cm) after 0.4 seconds? Take up to be positive...
5. ### Finding the half-life of an unknown substance

More Help, Please... I have two more parts to this problem: (a) How much will be left after 75 days? (b) How long will it take the 1000 particles to decay to a single particle? For (a), I came up with: 324.656 particles For (b), I came up with: 460.521 days Will you please verify...
6. ### How long does it take to boil away 0.4L water from a copper pot?

Thanks I did get 1.478607576 seconds, rounded to 1.48. I just forgot to take the thickness of the pot into consideration. Thanks for the help.
7. ### How long does it take to boil away 0.4L water from a copper pot?

This one has me stumped. Please help me solve. Thank you! Time A copper pot is heated by a burner which is at 195 ° C. If the water in the pot is boiling, how long does it take in seconds to boil away 0.4 L? The diameter of the pot is 27 cm, and it is 3.5 mm thick. k copper = 9.4...
8. ### Finding the half-life of an unknown substance

Is this correct? I used, based on the above: N(t) = N base0^(-lambda x /T), where T is the half-life t = 50 days N base0 = 1000 I rounded to the nearest whole number for days and came up with 46. Is that correct?
9. ### Finding the half-life of an unknown substance

Thank you. I'll give it a try.
10. ### Finding the half-life of an unknown substance

1000 particles of an unknown radioisotope decays to 472.37 particles in 50 days. (a) What is the half-life of this substance? Any problems that I had done previously, the half-life was given. Any help will be greatly appreciated. Well, I know a few things, but don't know if they...
11. ### Fission and Barium-144

Does Barium-144 have any useful purpose? All I really know about it is that it is a product of fission (one of the fission fragments from Uranium), which then decays into La-144, Ce-144, Pr-144, and Nd-144. Some radioisotopes are used in the medical field. What does Barium-144 bring to...
12. ### Need help answering problems related to Buoyance/Buoyance Force

Here's what I have so far... I have the following, but I know my answer isn't correct because it's an online course and will let you know when you are correct: Let: Mm = mass of man in kg (given at 100 kg) Vm = volume displaced by man in m^3 = Mm/Dm Sg = specific gravity of seawater...
13. ### Need help answering problems related to Buoyance/Buoyance Force

I have two homework problems that I am unable to answer related to buoyancy/force. Please help! Thanks! 1. How much force (in Newtons) does it take to hold a 100kg man completely under water in the ocean? His density is 903 kg/m^3, and the specific gravity of sea water is 1.07. They...
14. ### Need Help Finding Magnitude of Uniform Cylinder

A uniform cylinder with a mass of 2.7 kg and a radius of 0.25 m is suspended by a string wrapped around it. As the cylinder descends, the string unwinds from it. What is the magnitude of the acceleration of the center of mass of the cylinder in m/s2? (Neglect the mass of the string and air...