using archimedes principle d1=density of liquid d2=density of substance. 500*d1g=1000*d2g d1=2d2 d1=1gm/cm3 d2=0.5 gm/cm3 after the block of mass m is placed , acc.to archimedes principle 1000d1g=1000d2g+m m=500g g=acceleartion due to gravity RATE ME IF I AM CORRECT