#### Answer

$3.643\times 10^{11}\ J$

#### Work Step by Step

The work done by a constant force ${\bf F}$ acting through a displacement ${\bf D}=\vec{PQ}$
is ${\bf W}={\bf F}\cdot{\bf D}$
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Defining a coordinate system with San Francisco at the origin, and Los Angeles on the positive x-axis, we have:
${\bf D}$=$\langle 605000\ m,\ 0\ m\rangle \quad {\bf F}=\langle 602148\ N,\ 0\ N\rangle$
${\bf W}=(602148\ N)(605000\ m)+0(0)=3.643\times 10^{11}\ Nm$
$=3.643\times 10^{11}\ J$