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  1. HRubss

    Calculating Flux over the closed surface of a cylinder

    For the mantel, the normal would be \hat{n} = \frac{<x,y,0>}{a} and for the disks, it would be \hat{n} = \frac{<0,0,z>}{b} From those two normal, I can take the dot product of normal with the vector and get the total flux? Sorry if I'm being slow...
  2. HRubss

    Calculating Flux over the closed surface of a cylinder

    Oh! I see what you mean. Would I have to add two more flux bounded by a circle to the total flux?
  3. HRubss

    Calculating Flux over the closed surface of a cylinder

    Wow haha, this would've save me more time My apologies, it should be \overrightarrow{r} = <acos\theta,bcos\theta , z> This is from the parametric description of a cylinder. End caps? My calculus is a bit rusty, its been about 2 years since I've worked on vector calculus.
  4. HRubss

    Calculating Flux over the closed surface of a cylinder

    I wanted to check my answer because I'm getting two different answers with the use of the the Divergence theorem. For the left part of the equation, I converted it so that I can evaluate the integral in polar coordinates. \oint \oint (\overrightarrow{V}\cdot\hat{n}) dS = \oint \oint...
  5. HRubss

    Determining the final velocity and acceleration magnitude traveling along an arc

    Oh! I see, because its a function of distance? So would ads = vdv be more appropriate? My "v" came from the constant acceleration formula but since it isn't constant, this will not work. The speed at A is 40 m/s? EDIT: Wait I figured it out! Since acceleration isn't constant and we're given...
  6. HRubss

    Determining the final velocity and acceleration magnitude traveling along an arc

    Can this be moved to introduction physics hw help forum? I think its better suited for there, even though this from an Engineering Dynamics textbook. EDIT: Thank you!
  7. HRubss

    Determining the final velocity and acceleration magnitude traveling along an arc

    Problem Statement: The motorcycle is traveling at 40 m/s when it is at A. If the speed is then decreased at v'=-(0.05s)m/s^2, where s is in meters measured from A, determine its speed and acceleration when it reaches B. I attached a picture of the problem. Relevant Equations: S = S_0 + v_0(t)...
  8. HRubss

    Medical What causes the risks of taking steroids?

    I appreciate the time you took to post this, this is very informative!
  9. HRubss

    Medical What causes the risks of taking steroids?

    If that’s the case, what’s your opinion on multivitamin tablets? I just looked at a bottle of multivitamins that I have (‘Opti-Men’). It says 3 tablets a day is one serving, and one serving contains 37.5 mcg of Vitamin D.
  10. HRubss

    Medical What causes the risks of taking steroids?

    Interesting, I was taught that exercising regularly has great benefits such as decreasing LDL and then to find out that taking steroids actually increases it. I wasn’t informed by anyone about steroids, just surfing the web for quick articles. When I was in high-school, we covered the risks of...
  11. HRubss

    Medical What causes the risks of taking steroids?

    I understand that anabolic steroids are a synthetic modification of testosterone, the natural body hormone. My question is, are the risks of taking steroids caused by defects in synthesizing the hormone or is it because of how the human body works to counteract the effects of adding more...
  12. HRubss

    Can water vapor go directly into a solid

    This graph should help you out. Of course, for water to freeze to a solid state it has be at 0* Celsius but that’s just half the puzzle. The atmospheric pressure has to be below 0.006 atm for it to go directly to a solid state instead of it at its triple point (where its solid, liquid, and gas...
  13. HRubss

    Studying What Should I Do If My Professors Don’t Teach?

    I’ve had success in reading the textbook before hand and then watching online lectures from MIT OCW or professors off of Youtube if something seems to dense for me to understand. It won’t be easy since it’ll be completely based off of how much work you put in yourself. If you still don’t...
  14. HRubss

    Specific Heat Problem, not getting the correct answer

    So... Substituting the entire formula: CMΔT(copper) + CMΔT(water) = -CMΔT(iron) I know that ΔT of copper and water should be the same and I want to get all the T(final) all on one side: ΔT(CM(copper) + CM(water)) = -CMT(final, iron) + CMT(initial, iron), and from here, I split up the ΔT of...
  15. HRubss

    Specific Heat Problem, not getting the correct answer

    So the equation should be like this? ΔQ(copper) + ΔQ(water) = - ΔQ(iron)
  16. HRubss

    Specific Heat Problem, not getting the correct answer

    Homework Statement A copper pot with a mass of 0.500 kg contains 0.170 kg of water, and both are at a temperature of 20.0°C. A 0.250-kg block of iron at 85.0°C is dropped into the pot. Find the final temperature of the system, assuming no heat loss to the surroundings. Homework Equations Q =...
  17. HRubss

    Radius of largest possible loop of an Airplane.

    Homework Statement A 2250 kg airplane makes a loop the loop (vertical circle) at a speed of 320 km/hour. Find (a) the radius of the largest circular loop possible and (b) The force on the plane at the bottom of this loop. Homework Equations F = m*a Centripetal Force = m * (v2)/r "Critical...
  18. HRubss

    Projectile motion HW check

    Though we used the range of 3m in the y direction, realistically, the ball would have hit the post and bounced off but we neglected that while we worked the problem out.
  19. HRubss

    Projectile motion HW check

    Nevermind, figured it out after reading part of my textbook. Thanks for the help guys.
  20. HRubss

    Projectile motion HW check

    When my professor worked it out, he did the exact same thing. Question though, how did you get ##t = T_1 \equiv 2 v_y/g##?
  21. HRubss

    Projectile motion HW check

    Yes, here's the worksheet.
  22. HRubss

    Vector components

    If it were from the x-axis, then the angle would be 57.1°
  23. HRubss

    Projectile motion HW check

    I think I found my answer but I'm not proud of it because I used parts of what someone else did on chegg.com but I understand the method. velocity in the x-direction: x = v(t) substitution x = (vcos40°)t plugging in the total distance from the problem.. 42m = (vcos40°)t bringing the t to the...
  24. HRubss

    Free-fall problem check

    This is very true, I just check both equations and got the same thing. Having the units cancel out helps.
  25. HRubss

    Free-fall problem check

    Thanks for your help, the answer seems so simple to achieve with just some critical thinking. I think I've just been spoon-fed so much to the point that I don't see the simple things anymore!
  26. HRubss

    Free-fall problem check

    Whoops, used -30m instead of -55m. It's not that I wanted to look up my answers, I just didn't trust my arithmetic and I wanted to see how the proper formula was achieved. The correct answer should be 30.6m/s or 31 m/s.
  27. HRubss

    Free-fall problem check

    Looking it up online, the proper equation should have been v0 = (Δy/t) - (at/2). Looks like instead of multiplying the constant of 2 like I did, they just inversely subtracted the +½(-9.81m/s2)(t2). For future experiences, I should just inversely bring over variables that have a constant in...
  28. HRubss

    Projectile motion HW check

    Wow, that completely slipped my mind. I wouldn't think the height of the ball reaches 3m since that's the height of the goal post, it would actually hit it if that were the case. How would I got about finding the correct height? I hope it's not something arbitrary..
  29. HRubss

    Free-fall problem check

    Okay, so he's what I did starting from the beginning.. I used 2 reference points for stone 1, one at the moment the stone is throwing upward with an initial velocity I need to find and the second one being at the point the stone reaches it's highest maximum height and falls to the ground. Stone...
  30. HRubss

    Projectile motion HW check

    When you say to use the goal post height and the angle of kick, finding the hypotenuse of the right triangle (assuming that the ball goes in a diagonal line)?
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