Question

A white billiard ball with mass mw = 1.43 kg is moving directly to the right with a speed of v = 3.4 m/s and collides elastically with a black billiard ball with the same mass mb = 1.43 kg that is initially at rest. The two collide elastically and the white ball ends up moving at an angle above the horizontal of θw = 39° and the black ball ends up moving at an angle below the horizontal of θb = 51°.

a. What is the final speed of the white ball?

b. What is the final speed of the black ball?

c. What is the magnitude of the final total momentum of the system?

d. What is the final total energy of the system?

Answer 1

a. Vw = 3.4 cos(39)
= 2.64 m/s

b. Vb = 3.4 cos(51)
= 2.14 m/s

c. mVo = 1.43 kg * 3.4 m/s
= 4.86 kg*m/s

d.E = 1/2 m v^2 = 1/2 (1.43) (3.4^2)
=8.27 J