Why are the values of mass and weight equal on earth?

The connection between mass and weight is with Newton's second law = Weight = Mass * g. If we assume g is 1, in common usage, then weight and mass are indeed equal. For a European physicist, g is about 9.81 (metres per second squared) so the weight of a 1 Kg object is 9.81 Newtons. read more

The units share the same name (pound), and values for weight and mass coincide at the Earth's surface, but only because of the origins of the units. In the metric system, units of mass (gram) and force (Newton) are clearly different. read more

Only the mass is the same everywhere. The weight (operational, as what you measure with a weighing scale) is the downward force of a mass on a surface. read more