Cosider a solid metal sphere (S) a few centimeters in diameter and a feather (f). For each quantity in the list that follows, indicate whether the quantity is the same, greater, or lesser in the case of (S) or in that of (f)? Explain in each case why you gave the answer you did. Here is the list; (a) the gravitational force; (b) the time it will take to fall a given distance in air; (c) the time it will take to fall a given distance in a vacuum; (d) the total force on the object when falling in vacuum.