17. Two masses, m1 and m2 are separated a distanced. What changes in the variables will result in no change in the
gravitational force between the masses?.
(More than one answer is correct)
a. m1 is double and dis doubled.
b. m2 is tripled and dis quadrupled.
c. Both m1, and m2 are tripled and dis tripled.
d. m2 is quadrupled and d is doubled.

Total solidification times of three casting geometries are to be compared: a sphere, a cylinder, in which the length-to-diameter ration - 1.0, and a cube. volume = 1000 cm^3 for all three shhapes, and the same casting alloy is used. a) determine the solidification times of each geometry b) based on the results of part (a), which geometric element would make the best riser? c) if the mold constant = 3.5 min/cm^2 in chvorinov's rule, compute the total solidification time for each casting.