An object at rest stays at rest and an object in motion stays in motion with the same speed and in the same direction unless acted upon by an unbalanced force.
The Ball will not stop until stopped by the baseball glove.
The Bus picks up children
The acceleration of an object as produced by a net force is directly proportional to the magnitude of the net force, in the same direction as the net force, and inversely proportional to the mass of the object.
The Bus has less acceleration now that there are more children on.
The Green haired child will jump in the water
For every action there is and equal opposite reaction.
When they jumped in they also pushed the boat backwards.