(a)[1]
Define what is meant by gravitational field strength.
(b)[2]
Explain why the gravitational field strength may be taken as constant for changes in vertical position of a point mass near the Earth’s surface.
(c)[5]
The Earth’s path around the Sun is nearly circular, with a radius of $1.5 \times 10^8\,\text{km}$. Its orbital period is $365$ days. Find a value for the mass $M$ of the Sun. Show your working.