Calculate the total force on the earth due to venus, jupiter, and saturn, assuming all four planets are in a line. the masses are mv=0.815me, mj=318me, msat=95.1me, msun=1.99x10^30kg, me=5.98x10^24kg and the mean distances of the four planets from the sun are 108, 150, 778, and 1430 million km. apparently the answer is 9.56x10^17 n but i'm not sure how to get to that