How many gold atoms are in a 1kg gold bar?

Arunner is training for an upcoming marathon by running around a 100-m-diameter circular track at constant speed. let a coordinate system have its origin at the center of the circle with the x-axis pointing east and the y-axis north. the runner starts at (x, y) = (50 m, 0 m) and runs 2.5 times around the track in a clockwise direction.

What is the weight of a feather (mass = 0.0001 kg) that floats through earth's and the moon's atmospheres?

Why does gravity have a lesser than grater effect on higher altitudes?