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2 physics questions that I came up with that has been bothering me

  1. Jul 9, 2013 #1
    1. If a car is moving at a given speed up a ramp at a given angle, how do I find the measurement of the arc of the parabola in which the car creates upon taking flight into the air. Also given that we know the mass of the car aswell.

    2. Simple. Why does kinetic energy leave a ball when I throw it? Also is the rate in which an object looses kinetic energy the same universally?Also would the mass of the object play a role in the loosing of energy?

    Thank you so much you guys!
     
  2. jcsd
  3. Jul 9, 2013 #2
    A ball gains kinetic energy when you throw it, it doesn't leave it. That comes later after you've thrown it.
     
  4. Jul 9, 2013 #3
    1. Use Newton's laws to find the x as a function of time, find the y as a function of time, then plot x vs y and get y as a function of x. You get a partial parabola. Then use some calculus to get the length of the curve.

    2. Friction with the air. The mass and shape of the object are factors in determining how fast it slows due to air resistance.
     
  5. Jul 10, 2013 #4
    do you mean x being the time that it goes off the ramp and y as the time it touches the ground? sorry im not understanding.However, I do understand the calculus part of finding the measurement of the curve but how could i sketch out an accurate parabola that the car would make which of course must be done before the calculus. Without actually doing a physical experiment.

    Also, I've been asking this question to multiple people and many said that it matters how much the car weighs. I know from Physics that when i throw a ball horizontally off a tower, the ball would take 2 times the height of the tower divided by 9.81 and all of this square rooted seconds to hit the ground and I multiply the seconds by the velocity in which I threw it to get the distance from the tower. Upon learning this from a Physics text book, it never mentioned anything about the mass of the ball that is thrown. Also, With question number one, could I use that same equation whereas the tower would be the ramp?
     
    Last edited: Jul 10, 2013
  6. Jul 10, 2013 #5
    For for a good start on your question 1, see the wiki on

    "Trajectory_of_a_projectile"

    though it neglects the air friction. But in physics, you have to walk before you run! Once you understand the simpler (no friction) analysis you can delve into the more complicated and realistic analysis.
     
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