ICSE Class 9 Answered

Let 'g' be the acceleration due to gravity

      'p' be the density of water, so, p = 1 g/cm ³ 

      'V' be the volume of the ball

      'q' be the density of the ball

Volume of ball within water = V – (1V/3)

                                             = (2V/3)

                                             = Volume of water displaced by the ball

Weight of the water displaced = (2V/3) × p × g

Weight of the ball = V × q × g

Since, the ball is floating

(2V/3) × p × g = V × q × g

=> q = (2/3) x p

=> q= (2/3) x 1

Therefore, the density of the cork is (2/3) g/cm ³