Physics
Physics
Problem
A student carries the same metal block first to the surface of the Moon and then back to Earth. The block is weighed at both places using (A) a beam balance and (B) a spring balance. a. (i) Explain why instrument (A) gives the same reading on the Moon as on Earth. b. (ii) Explain why instrument (B) gives different readings at the two places. c. (iii) Define inertial mass and gravitational mass. d. (iv) State which of the two instruments measures inertial mass and which measures gravitational mass, giving reasons.Intuitive explanation
The key is understanding that weight and mass are different, and the two scales measure them differently. A beam balance compares masses by balancing gravitational forces, so it reads the same on the Moon and Earth—mass doesn't change. A spring balance stretches based on the actual gravitational force pulling down, which is much weaker on the Moon, so it reads less there. This problem tests whether you can distinguish between an object's intrinsic mass and its weight in different gravitational fields.
Intuitive explanation
The key is understanding that weight and mass are different, and the two scales measure them differently. A beam balance compares masses by balancing gravitational forces, so it reads the same on the Moon and Earth—mass doesn't change. A spring balance stretches based on the actual gravitational force pulling down, which is much weaker on the Moon, so it reads less there. This problem tests whether you can distinguish between an object's intrinsic mass and its weight in different gravitational fields.