Question

A man weighs 600 N on the earth. What is his mass? (take $g=9.8m{s}^{-2}$). If he were taken to the moon, his weight would be 100 N. What is his mass on the moon? What is the acceleration due to gravity on the moon? [3 MARKS]

Answer 1

Problem: 3 Marks

Given, weight of man on earth, $W_e=600N$
weight of man on moon, $W_m=100N$ and acceleration due to gravity, $g=9.8m{s}^{-2}$
Let 'm' be the mass of the man.
We know, $W=m\times g$
$\therefore W_e=m\times g$
$\Rightarrow m=\frac{W_e}{g}=\frac{600}{9.8}=61.22kg$

Thus, the mass of man on the earth is $61.22kg$. Now, the mass of a body remains the same everywhere in the universe. So, the mass of man on the moon will also be $61.22kg$.

We will now calculate the value of acceleration due to gravity on the moon by using the same formula:
$W=m\times g$
i.e, $W_m=m\times g$
where mass, $m=61.22kg$
$\Rightarrow g=\frac{W_m}{m}=\frac{100}{61.22}=1.633m{s}^{-2}$
Therefore acceleration due to gravity on the moon is $1.633m{s}^{-2}$.