0
yeah
yes
Nope.
Rock It - album - was created in 1979.
Original force = G (M1) (M2) / (R)2
New force = G (2M1) (2M2) / (2R)2 = (2 x 2)/(2)2 times G (M1) (M2) / (R)2 = same as the original force.