One knows from the situration that convservation of momentum is conserved, in all directions. From symettry, one knows that the two balls move symettrically, that is, the vertical momentums are in opposite directions. Conservation of energy has to be assumed, even though the problem did not state elacticity.
mv1=mv2cosTheta+mv3cosTheta
1/2 mv1^2=1/2m(v2costheta)^2 +
1/2m(v3cosTheta)^2+1/2m(v2sinTheta)^2+
1/2m(v2sinTheta)^2
From those two equations, one can determine v2, and v1. Remember that v2=v3
ball 1 with an initial speed of 10 m/s collides elastically with stationary balls 2 and 3 that are initially in contact with each other. the centers of balls 2 and 3 are on a line perpendicular to the initial velocity of ball 1. the three balls are identical. ball 1 is aimed directly at the contact point, and all motion is frictionless.
a) after the collision, what are the velocities of balls 2 and 3?
b) what is the velocity of ball 1 after the collision?
2 answers
this is 8 years late but he is wrong