units of mass: gram (g) - kilogram (kg) -tongram : equal to mass of paper clipkilogram: is equal to mass of one liter of water.

note:2kg=............liters=............grams

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 thegravitational force of the planet decrease as object move away.