The mass of a block made of a certain material is 13.5 kg and it’s volume is 15 x 10^-3 m³. (a) Calculate upthrust on the block if it is held fully immersed in water. (b) Will the block float or sink in water when released? Give reason for your answer. (c) What will be the upthrust on block while floating? Take density of water = 1000 kg m^-3.

(a) Mass of block = 13.5 kg

Volume of block = 15 × 10^-3 m³

Density of water = 1000 kg m^-3

Upthrust = volume of block × density of water × g

Substituting the values in the formula above, we get, upthrust on block,

Upthrust on the block = 15 × 10^-3 × 1000 × g = 15 kgf

(b) The upthrust on the block when fully immersed is 15 kgf which is more than its weight of 13.5 kgf hence the block will float in water when released.

(c) The block will float with its that much part submerged for which upthrust becomes equal to its weight of 13.5 kgf. Hence while floating, the upthrust on the block will be 13.5 kgf.