Recent content by Zach Knight

  1. Z

    Work Done By A Force of Constant Magnitude in Moving an Object in a Circle

    Okay. I think I see where I went wrong with the line integral approach too. Because the force is applied perpendicular to the motion, \vec{F} should equal -F\cdot cos(\theta) \cdot sin(\omega t)\hat{i}+F\cdot cos(\theta) \cdot cos(\omega t)\hat{j}.
  2. Z

    Work Done By A Force of Constant Magnitude in Moving an Object in a Circle

    Homework Statement A wagon is drawn by a student pulling with a constant force of F Newtons applied at an angle of θ° to the horizontal. If the wagon is drawn in a circle with radius r meters, how much work is done on the wagon? (I don't remember the actual numbers) Homework Equations...
  3. Z

    What is the Apparent Weight in an Accelerating Elevator?

    Homework Statement While stationary on Earth you have a weight of 550N. When in an elevator that accelerates upward your weight temporarily becomes 590N. When descending, your weight temporarily becomes 510N. Find a) the acceleration you experience as the elevator moves up and b) the...
  4. Z

    Finding the Indefinite Integral of a Radical Expression

    Ah, that's it! Somehow, I got the derivative of csc(theta) as -sin(theta)cos(theta). I guess it's time for me to go to bed :smile:
  5. Z

    Finding the Indefinite Integral of a Radical Expression

    Sorry, I combined arctanh and tanh-1 Anyway, how are the two equivalent? I'm not very familiar with hyperbolic trigonometry.
  6. Z

    Finding the Indefinite Integral of a Radical Expression

    Homework Statement \int{\sqrt{1+e^x}dx} Homework Equations \int{uv'}=uv-\int{u'v} The Attempt at a Solution I rewrote the integrand as \sqrt{1+(e^{x/2})^2} and used the trigonometric substituition e^{x/2}=tan(\theta), which simplified the radical to...
  7. Z

    Parametric to Polar Conversion

    The thing is, I don't have the parametric equations; I'm trying to find them via a differential equation. I'm trying to formulate \frac{d^2\vec{r}}{dt^2}=\frac{-MG}{|r|^3}\vec{r} in terms of \theta because the only way I could find to solve the above equation was to assume |r| was a constant...
  8. Z

    Trig Identity: Solving Cos(x/2) = 1/2 and the Proper Use of Plus or Minus

    Apphysicist and Mentallic are both right on this one. Taking the arccos first will give you two answers since cos is positive in two quadrants. Not quite sure what gb7nash is talking about.
  9. Z

    Sets and Logics, problem to solve a question

    Consider the number 152 in base 10. Another way to write this number is 2*100+5*101+1*102. If we change the base, we just change all of those tens. For example 152(base 8)=2*80+5*81+1*82=2+40+64=106(base 10) Can you write AC3(base 16) in the form above?
  10. Z

    Parametric to Polar Conversion

    Homework Statement Convert the two equations x=x(t) and y=y(t) to a polar equation of the form r=r(\theta) Homework Equations x=r*cos(\theta) y=r*sin(\theta) r^{2}=x^{2}+y^2 The Attempt at a Solution Perhaps I'm over-thinking this, but in order to eliminate the parameter t, I...
Back
Top