Question

On a stationary sail – boat, air is blown at the sails from a fan attached to the boat (from inside the boat). If the river is still, the boat will

• A. Remain stationary
• B. Spin around
• C. Move in a direction opposite to the which air is blown
• D. Move in a same direction in which air is blown

Answer 1

The correct option is A Remain stationary

The force due to air will form an internal force.

Only external forces can change the velocity of a system in the absence of which the boat remains stationary.