What is the net force acting on the piano?
11,500 N
-11,500 N
500 N
-500 N

the answer is zero. the net force on the piano is zero

Explanation:

11,500 N and - 11,500 N cancel each other out and the same goes with 500 N and -500 N.

you go to your settings preference and in the end youll see sth that says "i want to delete my acc" click on it and u'll acc will be deleted but u have to wait.

i believe the answer would be:

d. violin, clarinet, french horn, and tuba