Recent content by johnsholto

  1. J

    Solving the separable ODE (x²+6x+12)dy=y²dx

    So the integral must be √3 *arctan(√3 *(x+3))+C. Which would give us y=-1/√3 *arctan(√3 *(x+3))+C
  2. J

    Solving the separable ODE (x²+6x+12)dy=y²dx

    I did try that, but I don't know how to integrate 1/x^2+6x+12 easily.
  3. J

    Solving the separable ODE (x²+6x+12)dy=y²dx

    Homework Statement I need to solve for a general solution of the following equation: (x^2+6x+12)dy=y^2dx 2. The attempt at a solution I tried using the method for seperable ODEs and got the following: ∫(x^2+6x+12)dy=∫(y^2)dx (x^2+6x+12)y=(y^2)x+C (x^2+6x+12-C)/x=y
  4. J

    Calculating the Speed of an Object Launched by a Spring Catapult

    A spring catapult consists of a massless spring and a massless cup. An object of a certain mass is loaded into the cup, the spring is extended to a length L, and the object is launched horizontally. What is the speed of the object? s is the natural length of the spring, L is the length...
  5. J

    How do you find planet radius from horizon angle and cliff height without a calculator?

    Punishment. Alas, I just remembered small angle approximation. cosA = 1-(A^2/2) cosA = R/R+100 R ≈ 8000000 I did not enjoy this problem.
  6. J

    How do you find planet radius from horizon angle and cliff height without a calculator?

    I tried it with: AB^2 + R^2 = (R+100)^2 AB = (R+100)sinA But i can't solve the equation without the calculator.
  7. J

    How do you find planet radius from horizon angle and cliff height without a calculator?

    A person stands on a cliff overlooking the sea. He is 100m above the sea level and he observes the horizon to be 5mrad below the local horizontal. How do you calculate the radius from this information without using a calculator? Trigonometry I am guessing, but I need a better hint.
  8. J

    What is the comet's maximum speed at its farthest distance from the star?

    What about angular momentum? mvr=mVR 50*4*10^10=x*10*10^10 x=20
  9. J

    What is the comet's maximum speed at its farthest distance from the star?

    A comet orbits a star. At its closest approach (r=4*10^10 km) it has a speed of v=50 km/s. How fast is the comet at its maximum distance (R=10*10^10 km)? Could someone verify my results? F=GMm/r^2=mv^2/r f=GMm/R^2=mV^2/R F/f = R^2/r^2 = Rv^2/rV^2 -> R/r = v^2/V^2 R=2.5r -> 2.5r/r...