Astronomy Practice Exam 2025 – Complete Preparation Guide

On the Moon, weight decreases, while mass remains constant. This distinction stems from the understanding of how weight and mass are defined in physics. Mass refers to the amount of matter in an object and is a scalar quantity that does not change regardless of location. It is intrinsic to the object itself.

Weight, on the other hand, is the force exerted on an object due to gravity and is dependent on both the mass of the object and the gravitational field strength acting on it. The gravitational pull of the Moon is about one-sixth that of Earth's. Therefore, when an object is on the Moon, its weight is significantly less due to this reduced gravitational force.

For example, if you weigh 60 kilograms on Earth, you might weigh only about 10 kilograms on the Moon. Despite this reduction in weight, your mass remains 60 kilograms because it doesn't change with location. Understanding this relationship clarifies why the correct answer notes that your weight decreases while your mass stays the same when moving from Earth to the Moon.