Recent content by 3.211k

  1. 3

    Friction Force & Direction for 925 kg Car at -12.2m/s2 Acceleration

    The problem only asks for F_f :smile: The free body diagram is the way to go. Fn and Fg cancel out. What other force or forces provide the acceleration?
  2. 3

    Please someone help me answers this questions im desperate

    Are you stuck for a topic? How about the Haber process? It was invented to manufacture ammonia which is needed for making fertilizer and explosives. So you could use it in a project about farming. http://www.idsia.ch/~juergen/haberbosch.html
  3. 3

    Calculating pH & pOH of AgNO2 Solution

    Is this correct? If Kb = kw / ka Kb = 1x10^-14 / 7.2x10^-4 kb = 1.3889x10^-11 I wonder if you've missed a couple... decimal places :) Do you have the answer for this question? I think I can help you but it's been awhile since I've done these kind of questions.
  4. 3

    Calculating pH & pOH of AgNO2 Solution

    So you know that NO2 is what will change the pH (and pOH). But what if we are only talking about a few NO2 ions? Will that change the pH by much? What if there are a whole bunch of NO2 ions available? Try to determine how much N02 has dissolved and is floating around in the water ready to react...
  5. 3

    Physics & Religion: Can You Believe in Cosmology & Unified Theory?

    For certain. Just look at a chain email that has been continually circulating for the last couple years: http://www.snopes.com/religion/einstein.asp" [Broken]
  6. 3

    Physics & Religion: Can You Believe in Cosmology & Unified Theory?

    I'm not sure I agree with the way this is phrased, but it comes down to definitions. I think that many questions about things such as morality can actually be answered by science. However, science will never answer the big questions that keep some of us awake at night. Religions and...
  7. 3

    Calculating Time for Sound to Reach Bottom of Mine Shaft

    If time is distance divided by velocity, what does the "2" signify when you multiply it in the third line here?
  8. 3

    Adult Education Center: Finding the Right Balance for University Admittance

    There are, however, obviously some people who have successfully completed online courses. It's just that none of my schoolmates or myself have ever been able to. I used to overhear my school's counselor having conversations over and over where he would try to discourage people from taking online...
  9. 3

    Adult Education Center: Finding the Right Balance for University Admittance

    I would strongly recommend to avoid taking any online or correspondence courses. The success rate is extremely low. Even if you are the type of person who can learn independently, many people do not complete the course or stick to their planned schedule. Even if you start off strong in the...
  10. 3

    Rotational motion and law of gravity

    What is the question asking us to solve for? Do you have everything you need to solve for it? I often make a list of everything that's been given, even before starting. R=? V=? M=? m=? G=?
  11. 3

    Total Time Travelled for 400m by Bus

    Looks like you already solved this, good job. Using different words to do the same thing: |---1----->|---2--------->|---3------->| So you found t1 = 6 And you found that t3 = 4.5 Instead of d = vt + .5at^2 to find d1 and d3, you can also use average velocity. Vave= (v + v')/2 ...
  12. 3

    Physics Word Problem; Projectile Motion

    Wow, this is a fun little question. Here's an idea (double check this yourself - don't trust it!): In the horizontal direction: d = vt + .5at^2 120 = vt + 0 So horizontal velocity is: v = 120 / t So vertical velocity is: v = (tan30) x horizontal velocity v = (tan30) x 120 / t Now in the...
  13. 3

    Calculate Water Depth Using Sonar | Speed of Sound = 5300 km/h

    Your answer of .64km looks good to me (and seems like a reasonable depth). So this question seems to be mainly about unit conversions. Start with 870 ms . Now we know that ms means milliseconds, and that milli means 10^-3 So 870 ms = 870 x 10^-3 s = .87 s Or another way to think about...
  14. 3

    Rotational motion and law of gravity

    So the gravitational force must equal the net force? Which is the centripetal force. Fg=Fc So I think you got this far already, but it looks as though you made a small mistake on this next step when you came up with this equation: You may have forgotten to either include a mass term or...
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