Is gravitational pull strengthened by distance?

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.

When the magnetic domains in a material can be aligned, but eventually drift out of alignment, the material is

Achlorine atom has 17 protons and 18 neutrons. what is its mass number? what is its atomic number?