Question 5
A man whose mass on earth is 60 kg is taken to the moon, where the acceleration due to gravity is 1/6 of its value on earth. What are his mass and weight there, in that order? (On earth take g = 10 m s−2.)
The right answer is the one marked above.
Mass 60 kg; weight 100 N. Mass is the amount of matter contained in an object, so it is unchanged wherever it is taken.
weight on earth = 60 × 10 = 600 N
weight on the moon = 600 ÷ 6 = 100 N
Weight depends on g. Since g drops to a sixth, so does the weight.
That is why astronauts bound along on the moon — their mass is the same; all that changed is the force pulling them down.