A student from Sidney, Australia compares the distance he obtained from the 1-st spark mark to the 25-th spark mark, with the similar result of a student who did the experiment in Gaithersburg, Maryland. Both students operated identical setups powered with 60 Hz AC, reported no missing spark marks, and achieved precision of their measurements in four significant figures. What difference in the results was found

The difference is obviously due tithe different gravitational constants as a result of variation in radius if the earth in Maryland and sydney

So

To calculate the difference

We use

distance s = 1/2 gt²

T = time difference between first spark and 25th spark will now be

24x (1/F)

= 24/60

= 0.4 sec

Therefore differnce in reading will be 0.5 x(9.8104 - 9.7967)x 0.42

= 0.002877 units

the body's situation won't change the forces are equal opposit and on the same body