On a windless day, a sailor (m=75kg) decides he wants to go sailing (=300kg). In order to move on this windless day, he decides to mount a powerful battery operated fan )m=(20 kg) on the back of his sailboat and points the running fan at the sail. The fan can deliver air that pushes against the sail to the right with a constant force of 300N.

Question

On a windless day, a sailor (m=75kg) decides he wants to go sailing (=300kg).  In order to move on this windless day, he decides to mount a powerful battery operated fan )m=(20 kg) on the back of his sailboat and points the running fan at the sail.  The fan can deliver air that pushes against the sail to the right with a constant force of 300N.
7A.  If the sailboat is at rest and if the sailor runs the fan for 10 seconds, what will be the velocity of the boat at the end of 10 seconds?
7B.  Would the sailor travel faster with with the sail Down or the sail up?

bobpursley · Answer

a. zero. Newtons third law. b. down, as the fan will propel the ship, as in an airboat.

Brooke · Answer

5.79 sail down