A blue and a green billiard ball, each with a mass of 0.15 kg, collide directly. Before the collision, the blue ball had a speed of 3 m/s while the green ball had a speed of 2 m/s. After the collision, the blue ball stays in place while the green ball continues in motion.
In 3-4 sentences, represent the situation before and after the collision and calculate the speed of the green ball after the collision. Be sure to discuss direction.
1 answer
Before the collision, the blue ball is moving with a speed of 3 m/s towards the green ball which is moving with a speed of 2 m/s in the opposite direction. After the collision, the blue ball comes to a stop and the green ball continues in motion. To calculate the speed of the green ball after the collision, we need to use the principle of conservation of momentum. Since the blue ball comes to a stop, its momentum is zero after the collision. Therefore, the momentum before the collision is equal to the momentum after the collision. The momentum before the collision is (0.15 kg * 3 m/s) - (0.15 kg * 2 m/s) = 0.15 kg * 1 m/s. Since momentum is conserved, the momentum after the collision is also 0.15 kg * 1 m/s. And since the green ball is the only one in motion after the collision, its speed is 1 m/s.