Find its weight.
Show that its gravitational potential energy is $-1.77 \times 10^{7}\,\text{J}$.
Use the information in (a)(ii) to find the speed the rock must have as it leaves the Martian surface in order to escape the planet’s gravitational attraction.
Determine the temperature at which the root-mean-square (r.m.s.) speed of hydrogen molecules is the same as the speed found in (b). Hydrogen may be treated as an ideal gas. A molecule of hydrogen has a mass of $2\,\text{u}$. The mean translational kinetic energy $\langle E_{K} \rangle$ of a molecule of an ideal gas is given by $\langle E_{K} \rangle = \frac{3}{2} kT$, where $T$ is the thermodynamic temperature of the gas and $k$ is the Boltzmann constant.
State and explain one reason why hydrogen molecules may escape from Mars at temperatures below that calculated in (i).