Physics

Problem

Earth’s radius is approximately

6.4\times10^{3}\,\text{km}

. Up to what depth

d

below the surface will the acceleration due to gravity fall to

75\%

of its surface value? a)

3.2\times10^{3}\,\text{km}

1.6\times10^{3}\,\text{km}

0.8\times10^{3}\,\text{km}

4.8\times10^{3}\,\text{km}