Question

Two balls of 100 g and 200 g are moving along the same line and direction with velocity of 1 ms⁻¹ and 2 ms⁻¹ respectively. The collide and after the collision, the first vall moves at a velocity of 2 ms⁻¹. Determine the velocity of second ball.

Answer 1

m1=100g=0.1kg

m2=200g=0.2kg

u1=1m/s

u2=2m/s

Velocity of first ball after collision(v1)=2m/s

According to law of Conservation of Momentum,

Momentum before Collision=Momentum after Collision

$m1u1 + m2u2 = m1v1 + m2v2 \\ = > 0.1 \times 1 + 0.2 \times 2 = 0.1 \times 2 + 0.2v2 \\ = > 0.1 + 0.4 = 0.2 + 0.2v2 \\ = > v2 = \frac{0.3}{0.2} \\ = > v2 = 1.5$

Therefore,Final Velocity of the second ball=1.5m/s