To solve this problem, you can use the principle of conservation of momentum, which states that the total momentum of an isolated system remains constant unless acted on by an external force.
In this case, the boy and the ball make up an isolated system, so the total momentum of the system before and after the ball is thrown must be the same.
The momentum of an object is equal to its mass multiplied by its velocity, so the momentum of the ball before it is thrown is equal to 5.0 kilograms * 10 meters per second = 50 kilograms*meters per second.
The momentum of the boy before the ball is thrown is equal to 50 kilograms * 0 meters per second = 0 kilograms*meters per second, since he is not moving.
After the ball is thrown, the momentum of the boy is equal to 50 kilograms * V meters per second, where V is the velocity at which the boy moves forward.
The momentum of the ball after it is thrown is equal to (-5.0 kilograms) * (-10 meters per second) = 50 kilograms*meters per second.
Since the total momentum of the system must remain constant, we can set up the following equation:
50 kilograms * V meters per second + 50 kilogramsmeters per second = 50 kilograms * 0 meters per second + 50 kilogramsmeters per second
This simplifies to:
50 kilograms * V meters per second = 0 kilograms * meters per second
Solving for V, we get:
V = 0 meters per second
This means that the boy does not move forward after throwing the ball. This is because the force of the ball being thrown backwards is equal and opposite to the force of the boy moving forward, resulting in no net movement.