A geophysical survey team records the following values of the acceleration due to gravity g at different depths d below the Earth’s surface.
a. Depth d (km): 0, 200, 400, 600, 800, 1000
Measured g (m/s2): 9.80, 9.40, 9.00, 8.60, 8.20, 7.80
(a) Depth d (km): 0, 200, 400, 600, 800, 1000
Measured g (m/s2): 9.80, 9.40, 9.00, 8.60, 8.20, 7.80
(i) Plot a graph of g (vertical axis) against d (horizontal axis) on graph paper using a convenient scale.
(b) (ii) Using the straight-line portion of your graph up to a depth of 800 km, determine its slope and hence estimate the radius of the Earth.
(c) (iii) Extrapolate your graph to predict the depth at which g would become zero. Comment on the reliability of this prediction in view of Earth’s actual structure.