projection

  1. T

    B Question about finding the force using vector projections

    In my pre-calculus textbook, the problem states: A 200-pound cart sits on a ramp inclined at 30 degrees. What force is required to keep the cart from rolling down the ramp? The gravitational force can be represented by the vector F=0i-200j In order to find the force we need to project vector...
  2. I

    Projections and direct sum

    1. Homework Statement Let ##V = \mathbb{R}^4##. Consider the following subspaces: ##V_1 = \{(x,y,z,t)\ : x = y = z\}, V_2=[(2,1,1,1)], V_3 =[(2,2,1,1)]## And let ##V = M_n(\mathbb{k})##. Consider the following subspaces: ##V_1 = \{(a_{ij}) \in V : a_{ij} = 0,\forall i < j\}## ##V_2 =...
  3. redtree

    I Completeness relation

    Two questions regarding the completeness relation: First: I understand that the completeness relation holds for basis vectors such that ## \sum_{j=1}^{m} | n_{j} \rangle \langle n_{j} | =\mathbb{I}##. Does it also hold for unit-normalized sets of state vectors as well, where ## | \phi_{j}...
  4. F

    Statics Question: Projection

    1. Homework Statement What's the projection of the resultant force onto an said axis? 2. Homework Equations Sine Law, Cosine Law 3. The Attempt at a Solution For problem 2/20, the projection onto the b axis was found by multiplying the resultant force by the cosine of 30 degrees. Why does...
  5. A

    Draw the third view and the points on each view

    1. Homework Statement Draw the third view and the points on each view. In the first picture you have what the exercise has given us and in the second what I have drawn. I have turned the page so that the first view is the one on the left, the horizontal one is the one on the right. Is that OK...
  6. A

    Engineering Solved free exercises papers about right angle projections, (cross) section views

    I am looking for free solved exercises about: right angle projections, (cross) section views Here are some pictures of my book so you can understand what I am looking for http://1.1m.yt/3cNNDl-.jpg http://1.1m.yt/FekMn6x.jpg http://1.1m.yt/1t3KEer.jpg http://1.1m.yt/urA5V2_.jpg...
  7. A

    Are these projections correct?

    1. Homework Statement We have to make right angle projections of various objects. Are these projections correct? 2. Homework Equations 3. The Attempt at a Solution https://postimg.org/image/tg987f8bx/ https://postimg.org/image/rcyszr8j1/ https://postimg.org/image/64l4ibu25/...
  8. Z

    B Creating Equation Based on Data Set of x,y Values

    I'm attempting to reclaim lost knowledge... hopefully this works. I would like to take a data set I have x,y values and project the trend beyond the (10) values I currently have. For example, I have a graph with (10) values for x and y, but would like to graph the trend created by values 1-10 to...
  9. L

    I Converting Planck data for spherical projection

    Does anyone know how I could convert data from Planck, which appear as an oval shape, into a form that I can easily map onto a sphere (ie. a rectangular shape in 2:1 aspect ratio)? Here is an example Planck image: http://sci.esa.int/science-e-media/img/61/Planck_CMB_Mollweide_4k.jpg I see that...
  10. RoboNerd

    I Finding shortest distance between skew lines, checking work.

    Hi everyone. I was working on a problem for days. The problem statement is: "Consider points P(2,1,3), Q(1,2,1), R(-1,-1,-2), S(1,-4,0). Find the shortest distance between lines PQ and RS." Now, I did the following formula: PS dot (PQ x RS) / magnitude of (PQ x RS). (For skew lines) Now...
  11. N

    I Height reached by an object

    Hello everyone, I was playing around with some equations regarding air resistance. I tried to calculate the height that is reached by an object that is projected vertically into the air. However something seems to go wrong when integrating. Starting with the equation of motion \begin{align*}...
  12. Ernesto Paas

    I When can one clear the operator

    Hi all! I'm having problems understanding the operator algebra. Particularly in this case: Suppose I have this projection ## \langle \Phi_{1} | \hat{A} | \Phi_{2} \rangle ## where the ##\phi's ## have an orthonormal countable basis. If I do a state expansion on both sides then I suppose I'd get...
  13. A

    A Project img on X-Y surface to a cylinder placed in center...

    Hi , I came across a problem ,I've search a lot but couldn't exactly find the solution. here is my problem: suppose there is an image ( I call it IMG_A),place IMG_A in the X-Y plane , put a mirror cylinder at the center of IMG_A. what we see in the cylinder mirror is a deform image (I call it...
  14. M

    Project sharp shadows from LED

    Using a high-power LED light (the surface mount kind, about 4x4mm with 120 degree viewing angle) I'd like to project shadows of a fine metal mesh onto a wall. I have tried various lens arrangements and found that placing a pinhole in front of the LED makes the sharpest shadows. This makes...
  15. G

    Concentrating sunlight to accomplish projection (Art project)

    Hello! First of all I want to say that I am not a physicist, but an artist currently doing my master thesis. I have been trying to build a solar powered slide projector. It works very simple – I reflect sunlight through a slide and enlarge it with a lens. My problem was that I wanted more...
  16. R

    Speed Time Estimation from a video

    1. Homework Statement Watch the crash test video , and determine the following: 1. How fast is one of the crash test dummies thrown forward (the crash at :34 seconds) ? Pick either one, and be clear how you estimate this. 2. Assuming the speed you got from part (1), how high would a...
  17. N

    Very narrow beam projector

    I am working on a project where I have to project a logo on a very narrow angle like shown below: The projection distance will vary between 6-10 yards and at 10 yards the projected diameter will not be larger than 12inches so the beam angle needs to be less than 5 degrees. The idea is to...
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