Solve Elastic Collision: Find Velocity & Direction

AI Thread Summary
To solve for the missing velocity and direction of one ball in an elastic collision, use the conservation of momentum and energy principles. The total momentum before and after the collision must remain equal, which can be expressed in terms of the x, y, and z components. A vector diagram can aid in visualizing the directions of the velocities involved. By calculating the known velocities and applying the conservation equations, the unknown velocity can be determined. Understanding the 2D or 3D nature of the problem is crucial for accurate calculations.
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Given two balls of the same mass of known velocities and known direction (before and after collision) , only one of the ball is not given its velocity and direction before collision and i am supposed to find them .

As for the velocity , just take the sum be4 and after collision and evaluate the missing one .

How about the direction ? Do i draw a vector diagram ?
 
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To find the velocity remember Momentum and Energy are conserved.

Hard to understand from your question, but it sounds like they are both traveling different 2D or 3D directions before collision, thus when they collide you can remember that Momentum is conserved in the x, y, and z direction. so:
\Sigmapx=\Sigmap'x
\Sigmapy=\Sigmap'y
\Sigmapz=\Sigmap'z
 
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