Friday, February 6, 2015

Week 9 Discussion (2/6 - 2/12)

Turn in #14 is due Friday, Feb.13, 2015!

This is for discussing assignments from WEEK 9, including homework, turn-in #14, in-class work or lessons, or anything else related to the class from these weeks.  Please be sure to include your name at the end of your post for credit.  When answering a question, DO NOT GIVE SOLUTIONS! Provide hints or explain a method that you used, but do not give the final result.  As always, RESPECT IS A MUST! Anyone abusing this forum will be banned from future use (meaning, no extra credit!!!).

38 comments:

  1. Are we expected to use units when talking about the position, speed/velocity, and acceleration of vectors? Thanks,

    Safia Sayed

    ReplyDelete
    Replies
    1. You could just to be safe. If they didn't give units you could just say units for position, units/sec for velocity, and units squared/sec for acceleration.

      Sophia Pryor

      Delete
    2. If units are given in the problem, use them in your solution. Otherwise, they are not vital, but still good practice to include, as Sophia points out.

      Delete
  2. Since time isn't on either axis, how would we know how time plays a factor by just looking at a graph?

    Thanks,
    Rachel Hersch

    ReplyDelete
    Replies
    1. You cannot look at a graph in the x-y plane and know it is parametric. We can parameterize an curve, actually, so we must know (be told) that a given graph is parameterized.

      Delete
  3. When the velocity and acceleration vectors are perpendicular to each other, the object is undergoing circular motion; is this statement correct?

    Rafey

    ReplyDelete
    Replies
    1. Well, the object is neither speeding up nor slowing down, so...

      Delete
  4. Is it correct to assume that when asked for speed the answer will be a single value and when asked for velocity the answer will be in vector notation?

    Angela Satullo

    ReplyDelete
    Replies
    1. I believe that is correct^

      Fried

      Delete
    2. Acceleration and velocity are vectors if the position is a vector. Speed and length/distance are scalar quantities.

      Delete
  5. Whenever you're asked to find distance or speed, do you just plug the position and velocity vectors into Pythagorean Thereom?

    ReplyDelete
    Replies
    1. Yes, sort of. Speed is the magnitude of the velocity vector and distance is its integral.

      Delete
  6. I have a similar question, would you ever do the Pythagorean Theorem with acceleration?

    Thanks,
    Rachel Hersch

    ReplyDelete
    Replies
    1. Hmmm, I cannot think of a reason to do this. Maybe Ms.M has some advice for what physical quantity that would represent. I have never seen it used.

      Delete
  7. From my understanding, yes. Both quantities are scalars, so there should be no directional components.

    Rafey Rehman

    ReplyDelete
  8. On the test, will we need to know the vector rules of whether a object is speeding up or slowing down depending on the angle between the velocity vector and the acceleration vector? Thank you!
    - Maggie Hammond

    ReplyDelete
  9. On the AP exam, do we have to use the double bracket notation to convert the given quantity from a vector to a scalar?

    Zach Van Faussien

    ReplyDelete
    Replies
    1. You would not be marked down for using a single bracket, as some texts even use this notation (most do not, though). We use double brackets to signify that it is not an absolute value of a real number, but rather the length of a vector.

      Delete
  10. Are most vector questions in the multiple choice section or free response section of the AP exam?

    Amanda Bachand

    ReplyDelete
  11. For question 2c on the turn-in are we supposed to use the limits 0 to 4 to determine the number of times it passes through the point found in part a?

    - Daniel Honet

    ReplyDelete
    Replies
    1. I'm sorry, I don't have the turn in at home with me. If limits are given, then use them, yes.

      Delete
    2. Since this is a calculator problem, you can get the answer by graphing the equation and count how many times it passes through the point when the calculator is graphing the function.

      Angela Satullo

      Delete
  12. When finding the position of a particle but only given the velocity x and y, would you have to find the new position equations, and then use the given to find C and then plug the time into the new equations or is there an easier way to do this?

    Emma Gijsbers

    ReplyDelete
    Replies
    1. If you want the position vector function, then integrate the velocity vector and use your initial conditions. If you want a position coordinates (x,y), then you can use FTC: use the initial value and add the net change (definite integral).

      Delete
  13. Is there going to be surface area on the quiz tomorrow?

    -Laura Goo

    ReplyDelete
    Replies
    1. No, unless you include the surface area of the paper... 😃

      Delete
  14. If we have to find the angle measure of a vector on the quiz tomorrow, do we use radian or degree mode?

    -Lexi Kizy

    ReplyDelete
    Replies
    1. Either unit is acceptable as long as you specify, but finding angles between vectors is not a BC Calculus topic.

      Delete
  15. For question 2c on the turn in is it asking how many times the pineapple passes through the point in 4 seconds or how many times it passes through total?

    Sophia Pryor

    ReplyDelete
    Replies
    1. In the problem, it states that the pinapple moves during the time period from t=0 to t=4 seconds. And since we don't know if the pineapple's motion is defined by the same position equations provided on the interval (0, infinity), I would assume they mean the amount of times the pinapple passes through that point during the interval (0, 4).

      - Daniel Honet

      Delete
  16. Maybe this is a dumb question, but on #2 of the turn-in, is "a pineapple moves along the path" referring to the pineapple's velocity vector ("movement") or position?

    Thanks!

    ReplyDelete
    Replies
    1. The path is given by x(t) and y(t) which would represent the position of the pineapple. dx/dt and dy/dt would represent the velocity.
      -Allison Honet

      Delete
  17. Hi Mr.Wilson,
    Me and Michael Bajorek are working on our calculus project and we are doing the motion of a soccer ball being kicked. as part of our project could we find something like arc length or volume of a solid of revolution created by our x vs.t or y vs. t graphs?
    -Will Schwartz

    ReplyDelete
    Replies
    1. Yes, those would each fulfill a requirement. Keep in mind that you need a non constant acceleration, so projectile motion is not sufficient.

      Delete
  18. For the calc/physics project, the directions say we don't need two reference points for our video, but then it asks us to describe the motion mathematically from the perspective of two reference points. So do we need two or is one okay?

    -Julia Trombley

    ReplyDelete
    Replies
    1. Hi Julia, the two reference frames is a requirement for Ms. M (physics) and for your description. The calculus only needs to be performed on one reference frame.

      Delete