16) 2m/s²

Downward force (Weight of object) = 20 x 10 = 200N
Upward force = 120 + 120 = 240 N
Resultant force = 240-200 = 40 N

Force = mass x acceleration
40 = 20 x a
a = 40 ÷ 20 = 2 m/s²