Define mass and weight of an object. Write their S.I. units. An object has mass of 20 kg on earth. What will be its mass and weight on the surface of the moon ? (g on moon ï 1.6 m/s2)
Mass is the amount of matter in a substance. Its SI unit is kilogram (kg).
Weight on earth is the force of earth’s gravity on an object due to its mass. Weight of an object of mass ‘m’ is = mg. ‘g’ is acceleration due to gravity. SI unit of weight is Newton (N).
Mass on earth, m = 20 kg
Mass remains constant everywhere. So, mass on moon = 20 kg
Weight on moon = m × gmoon = (20)(1.6) = 32 N