What is the importance of universal law of gravitation?

What is the acceleration of free fall?

Amit buys few grams of gold at the poles as per the instruction of one of his friends. He hands over the same when he meets him at the equator. Will the friend agree with the weight of gold bought? If not, why? [Hint: The value of g is greater at the poles than at the equator.]

Why will a sheet of paper fall slower than one that is crumpled into a ball?