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Homework Help: Mastering Physics: Collision on an incline plane and perfectly inelastic collision

  1. Mar 13, 2005 #1
    Can anyone help me with theses problems?

    1. A 500 g cart is released from rest 1.0 m from the bottom of a frictionless, 30 ramp. The cart rolls down the ramp and bounces off a rubber block at the bottom. The figure shows the force during the collision.

    After the cart bounces, how far does it roll back up the ramp?

    On this one I know I need to solve for the velocities before and after the collision and then use this value to get the distance, but I am not sure as to how I need to do this. I don't really know how to get the acceleration.

    2. In a military test, a 575 kg unmanned spy plane is traveling north at an altitude of 2700 m and a speed of 450 m/s. It is intercepted by a 1280 kg rocket traveling east at 725 m/s.

    If the rocket and the spy plane become enmeshed in a tangled mess, how far from the point of impact do they hit the ground?

    This problem really has me puzzled. I tried to use the m1v1 + m2v2= m(1+2)v equation and solve for the magnitude of the velocity but am not sure where to go from there. Let me know where I went wrong. Thanks

    Attached Files:

  2. jcsd
  3. Mar 14, 2005 #2

    On the second one, you use the final velocity from the momentum equation and use that as the inital velocity in a projectile motion problem.

    On the first one, use a = gsin(theta) to get acceleration along the ramp.

    Hopefully these will help you go forward.
  4. Mar 14, 2005 #3
    Ok so when you use gsin(theta) as the acceleration, and find the velocity before the collision, do you plug this into the equation for an impulse (P2=J+P1)?

    On the second one, once you find the magnitude of the velocity you need to use the x and y components of the velocity in the projectile motion equations correct?
    Last edited: Mar 14, 2005
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