Menka Malguri
Last Activity: 13 Years ago
When the ball of mass m collides with the ball with velocity v1 making angle 30° with the normal to the wall,it rebounds with velocity v2 at an angle 30° to the normal on the wall (angle between the ball and the normal=90°-angle between the wall and the ball).Here,the speedc v1 and v2 are same but the directions are different,so the velocities are different.
now,change in momentum would be
Δp=mv1-mv2
Δp=m(v1-v2)
Subtracting the two velocities vectorially,we get,
Δp=m[√(v12+v22-2v1v2cosθ)],here θ is the angle between the two velocities.
Δp=m[√(v2+v2-2v2cos120°)]
Δp=m[√(2v2-2v2(-1/2))]
Δp=m[v√3]
so,the change in momentum is (mv√3).