A person travelling by a car moving at 100 km h^–1 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 km (in the earth’s frame) from the tower A when the car reaches there?

Time taken by the car to reach the tower B from tower A =.

As the frame of wrist watch is moving the wrist watch will lag by

Where , V is velocity of moving object and C is speed of light in vacuum i.e.

And is time in rest frame .

V=

as using binomial expansion we know we can write

when

Similarly, =

And as we can see the calculated value is too small to make drastic affect that’s why we don’t face any trouble in real life situation.