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9. A billiard ball of mass 0.15 kg approaches two other identical balls as shown

ID: 1289470 • Letter: 9

Question

9. A billiard ball of mass 0.15 kg approaches two other identical balls as shown.

The initial speed of the projectile ball is 0.2 m/s. After collision, the initial ball

is at rest and the two target balls move off at 45 degree angles to the initial

direction as shown. Find the speeds of the target balls after collision.

9. A billiard ball of mass 0.15 kg approaches two other identical balls as shown.

The initial speed of the projectile ball is 0.2 m/s. After collision, the initial ball

is at rest and the two target balls move off at 45 degree angles to the initial

direction as shown. Find the speeds of the target balls after collision.

9. A billiard ball of mass 0.15 kg approaches two other identical balls as shown. The initial speed of the projectile ball is 0.2 m/s. After collision, the initial ball is at rest and the two target balls move off at 45 degree angles to the initial direction as shown. Find the speeds of the target balls after collision.

Explanation / Answer

Momentum is conserved

Pinitial-x= Pfinal-x

Pinitial-x= 0.15*0.2m/s= 0.03kg m/s

Pfinal-x = m*Vcos[45]+m*Vcos[45]

Pfinal-x = 2m*Vcos[45]

0.03kg m/s= 2*0.15*Vcos[45]

0.03kg m/s= 0.212 *V

V= 0.142m/s

The speeds of the target balls after collision is 0.142m/s