Which feels a greater pull due to the earth’s gravity: a 10-kg stone or a 20-kg stone? If you drop the two stones, why doesn’t the 20-kg stone fall with twice the acceleration of the 10-kg stone? Explain.

Solution 26DQ Introduction We have to calculate the gravitational force in for each stone and then see which feels greater pull Solutio Step 1 The gravitational pull is given by GMm F = R2 Where m is the mass of the object, M is the mass of earth, G is the universal gravitational constant and R is the distance between the center of earth to the center of stone. So the gravitational pull on the stone with 10 kg mass is given by F = GMm210= GM(12 kg) 10 R R And the pull on the 20 kg stone is GMm 20 GM(20 kg) F 20 = R2 = R2 Here we can see that except m all other things remains same, hence we have F > F . 20 10 Hence the 20 kg stone feels greater pull due to gravity.