How many nutrons are in an atom of copper

There are two stable isotopes of copper. Their atomic weights are 63 and 65.

Since the atomic number of copper is 29, those isotopes' nuclei have 34 neutrons and 36 neutrons respectively.

when two balls of the different masses are dropped from equal height, they reach the ground at the same time .this is because they experience the same acceleration.

the acceleration is independent of mass.

thus when they are dropped they will always maintain the same velocity and travel the same distance (neglect air resistance of course) at the same time.