A body produces a reading of 800 N when placed on a weighing machine on the Earth’s surface.
(i) Determine the mass of the body.
(ii) The same body is carried to Mars where the acceleration due to gravity is 3.8ms−2. Calculate its weight on the Martian surface.
(iii) By what percentage does the numerical value of the body’s weight decrease on Mars compared with its weight on the Earth? Show your working clearly.
(iv) Explain why travellers to Mars must carefully recalibrate force-measuring instruments such as spring balances, while mass-measuring instruments such as equal-arm balances require no recalibration.