Question

An astronaut has 80 kg mass on earth :
(a) What is his weight on earth?

Answer 1

Step 1: Given data

Mass of the astronaut, $\mathit{m}\mathbf{=}\mathbf{80}\mathbf{}\mathit{k}\mathit{g}$

Mass remains constant throughout the universe.

Acceleration due to gravity on earth, $\mathit{g}\mathbf{=}\mathbf{9}\mathbf{.}\mathbf{8}\mathit{m}\mathbf{/}{\mathit{s}}^{\mathbf{2}}$

Step 2: Finding the weight of the astronaut on earth

$$\begin{gathered} {\mathit{W}}_{\mathbf{a}\mathbf{e}}\mathbf{=}\mathit{m}\mathit{g} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{=}\mathbf{}\mathbf{80}\mathbf{\times }\mathbf{9}\mathbf{.}\mathbf{8} \\ \mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{}\mathbf{=}\mathbf{784}\mathbf{}\mathit{N} \end{gathered}$$

Thus, the weight of the astronaut is $784N$.