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View Full Version : Law of Conservation of Momentum in 2 D


phys_08
Aug 5, 2009, 11:56 AM
A 6.0 kg object, A, moving at velocity 3.0 m/s, collides with a 6.0 kg object, B, at rest. After the collision, A moves off in a direction 40.0o to the left of its original direction. B moves off in a direction 50.0o to the right f A's original direction.

Draw a vector diagram and determine the momentum of object A and object B after the collision.

:)

galactus
Aug 5, 2009, 05:12 PM
Let f be the final velocity and i the initial velocity. Whenever two masses collide elastically in a glancing collision such as this one, their final velocities are always at right angles to each other. Think of this problem as playing a game of pool where A is the cue ball.

Since m_{1}=m_{2}, we can write:

v_{1f}cos(40)+v_{2f}cos(50)=3

v_{1f}sin(40)-v_{2f}sin(50)=0

v_{1f}^{2}+v_{2f}^{2}=3^{2}

Momentum is mv, mass times velocity.