The table below shows physical data for the hypothetical cold super-Earth Boreas-4c:
Mass / kg1.25×1025Radius / km8400Density of atmosphere at surface / kg m−358Period of rotation about its axis / hours14.2\begin{array}{|l|c|} \hline \textbf{Mass / kg} & 1.25 \times 10^{25} \\ \hline \textbf{Radius / km} & 8400 \\ \hline \textbf{Density of atmosphere at surface / kg m}^{-3} & 58 \\ \hline \textbf{Period of rotation about its axis / hours} & 14.2 \\ \hline \end{array}Mass / kgRadius / kmDensity of atmosphere at surface / kg m−3Period of rotation about its axis / hours1.25×102584005814.2
Calculate the magnitude of the gravitational field strength ggg at the surface of Boreas-4c. Give your answer to 3 significant figures.
Two identical robotic landers, Alpha and Beta, touch down on a flat ice sheet on Boreas-4c.
Lander Alpha lands at the north pole. Lander Beta lands on the equator.
Each lander has mass 1120 kg1120 \text{ kg}1120 kg and volume 3.6 m33.6 \text{ m}^33.6 m3.
Calculate the centripetal acceleration aaa of lander Beta at the equator due to the axial rotation of Boreas-4c.
The dense atmosphere exerts the same upthrust on each lander. Using your value of ggg from part (a), calculate the magnitude of this upthrust.
Explain which lander will experience the greater normal contact force from the surface of Boreas-4c.
