Newton’s second law gives us the following two equations:
FT − mg = ma (1)
Mg − FT = Ma (2)
Adding these equations yields Mg − mg = ma + Ma = (M + m)a, so
- E If Fnet = 0, then a = 0. No acceleration means constant speed (possibly, but
not necessarily, zero) with no change in direction. Therefore, (B), (C), and
(D) are false, and (A) is not necessarily true.
- D The horizontal motion across the frictionless tables is unaffected by
(vertical) gravitational acceleration. It would take as much force to
accelerate the block across the table on Earth as it would on the moon. (If
friction were taken into account, then the smaller weight of the block on the
