masa apei = volum * densitate=0,08m*0,08m*0,04m*1000 kg/m cub=0,256 kg=256g apa
densitate material vas = masa vas / volum vas= (0,506-0,256)/100cm cub=
=0,250kg/(100/1000000)m cub=0,250kg/0,0001 m cub=2500 kg/m cub =>
material vas = sticla
masa ulei = volum ulei * densitate ulei=0,08m*0,08m*(0,05-0,04)m*800 kg/m cub=0,0512 kg=51,2g ulei