# Shi Qi 4 Mar 2018 - 1

## Question

At a point outside the Earth and a distance of x from its centre, the Earth’s gravitational field strength is 5 N kg-1. At the Earth’s surface, the field strength is about 10 N kg-1. Which of the following gives an approximate value for the radius of the Earth?

A) x/5

B) x/2√2

C) x√2

D) x/√2