a) H=120cm

r=1,2cm

$V=\pi r^{2}H=3,14\cdot {1,2}^2\cdot 120=542,6c{m}^3$

waga= $542,6\cdot 0,5=271,3g$

b) H=30m=3000cm

r=1mm=0,1cm

$V=\pi r^{2}H=3,14\cdot {\left(0,1\right)}^2\cdot 3000=94,2c{m}^3$ $V=\pi r^{2}H=3,14\cdot {\left(0,1\right)}^2\cdot 3000=94,2c{m}^3$

$waga=94,2\cdot 8,96=844g$

c) $r_z=6cm$

$r_w=4cm$

H=1m=100cm

$V_z=\pi r^2\cdot H=3,14\cdot 6^2\cdot 100=11304c{m}^3$

$V_w=\pi r^2\cdot H=3,14\cdot 4^2\cdot 100=5024c{m}^3$

V=11304-5024=6 $280c{m}^3$

$6280\cdot 7,8=48984g=48,984kg$

d) H=16cm

r=1mm=0,1cm

$V=\pi r^2\cdot H=3,14\cdot {\left(0,1\right)}^2\cdot 16=0,5024c{m}^3$

$waga=0,5024\cdot 2,3=1,16g$