David Sang and Graham Jones Solutions for Chapter: Gravitational Fields, Exercise 3: Questions

Calculate the gravitational field strength close to the surface of the Sun. 

Suggest how your answers help to explain why the Moon has only a thin atmosphere, while the Sun has a dense atmosphere. 

Calculate the Earth's gravitational field strength at the position of the Moon. 

Calculate the force the Earth exerts on the Moon. Hence, determine the Moon's acceleration towards the Earth. 

Jupiter's mass is $320$ times that of the Earth and its radius is $11.2$times the Earth's. The Earth's surface gravitational field strength is$9.81 {\mathrm{Nkg}}^{-1}$. Calculate the gravitational field strength close to the surface of Jupiter.

The Moon and the Sun both contribute to the tides on the Earth's oceans. Which has a bigger pull on each kilogram of seawater, the Sun or the Moon? 

Astrologers believe that the planets exert an  influence on us, particularly at the moment of birth. (They don't necessarily believe that this is an effect of gravity!) Calculate the gravitational force on a $4.0 \mathrm{kg}$ baby caused by Mars when the planet is at its closest to the Earth at a distance of $100 000 000 \mathrm{km}.$ Mars has a mass $6.4\times {10}^{23}\mathrm{kg}.$

Astrologers believe that the planets exert an influence on us, particularly at the moment of birth. (They don't necessarily believe that this is an effect of gravity!). Calculate the gravitational force on the same baby due to its $50 \mathrm{kg}$ mother at a distance of $0.40\mathrm{m}.$