A 10,000 N piano is dropped from the top of a building. When the piano reaches terminal speed ...

a. What is the net force on the piano?

b. What is the force of air resistance on the piano?

a). When the piano reaches terminal speed, it is no longer accelerating,

so the net force on it must be zero.

b). If the net force on the piano is zero, the upward force of air resistance on it

must be exactly equal to the downward force of gravity ... 10,000 N.