❗❗100points❗❗ Hey can any1 tell me how I answer question a, I just don't understand what am supposed to write, can sb explain it?? thanks ♡

If forces acting on an object are unbalanced. true or false

Aball of mass 0.3kg is released from rest at a height of 8m.how fast is it going when it hits the ground? accleration due to gravity is g=9.8m/s

The molecular weight of oxygen gas (o2) is 32 while that of hydrogen gas (h2) is 2. prove that under same physical conditions, the velocity of sound in hydrogen is four times that in oxygen