Question

Half the volume of the block immersed in water.what is the reading of the spring balance?(Density of water=1.0gcm^-3)

Answer 1

At equilibrium the force acting on a spring

$$F=mg-F_{buoyant}=g\rho V-g\rho_{water}V/2$$

$$F=gV(\rho-\rho_{water}/2)$$

Here $V$ is the volume of the block, $\rho$ is the density of block material.