# a fan on a floating barge blows air at high speed toward the right.

a)will the barge move? if so, what direction? explain.
B) a sail is now put up on the barge so that the fan blows air towards the sail. will the barge move. if so, what direction? explain.

## a) The barge will move in the opposite direction that is pushes the air. Think of Newton's Third law here. The force of the fan blades upon the air equals the force of the air on the fan.

b) In this case the barge may move, but very little. Assuming no natural wind, the force of the fanned air hitting the sail will be nearly equal and opposite to the force of the air on the fan blades. The sail takes away the momentum of the air directed at it by the fan.

## a) Yes, the barge will move. When the fan blows air at high speed toward the right, it creates a force in that direction, exerting a pressure on the air molecules. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. As a result, the air exerts a force on the fan in the opposite direction, pushing the fan and the barge towards the left. Therefore, the barge will move in the left direction.

b) Yes, the barge will move. When the sail is put up on the barge, the fan blows air towards the sail. The sail acts as a surface that catches the moving air molecules, causing a force to be exerted on the sail. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. As a result, the air exerts a force on the sail in the opposite direction, pushing the sail and consequently the barge towards the right. Therefore, the barge will move in the right direction.

## a) Yes, the barge will move. According to Newton's third law of motion, for every action, there is an equal and opposite reaction. When the fan blows air at high speed towards the right, it creates a force in the opposite direction. The air exerts a force on the fan, and the fan exerts an equal and opposite force on the air. As a result, the air pushes the fan towards the left, and by Newton's third law, the fan pushes the barge towards the right.

b) When a sail is put up on the barge so that the fan blows air towards the sail, the barge will move in the same direction as the force applied by the fan. The air blown by the fan hits the sail and creates a force in the opposite direction. As per Newton's third law, the air exerts a force on the sail, and the sail exerts an equal and opposite force on the air. This force on the sail moves the barge in the direction opposite to that of the force applied by the fan. Therefore, the barge will move in the direction opposite to that of the fan's air flow, which is towards the left.