units of mass: gram (g) - kilogram (kg) -ton gram : equal to mass of paper clip kilogram: is equal to mass of one liter of water.
1 Newton =100 grams , 2 N = 200 grams
note: weight increase as mass increase and vice verse. 2- mass = weight /10
as mass of planet increase as weight increase why? due to gravitional force increase
weight decrease as the object move away from the centre of the planet bec the gravitational force of the planet decrease as object move away.