Question:
A person travelling by a car moving at a speed of $100 \mathrm{~km} / \mathrm{h}$ finds that his wristwatch agrees with the clock on a tower A. By what amount will his wristwatch lag or lead the clock on another tower B, $1000 \mathrm{~km}$ (in the earth's frame) from the tower A when the car reaches there?
Solution:
