For a static fluid, pressure variation is defined by the equation:
\[\frac{dp}{dy} = -Y,\]
where:
$p$ represents pressure,
$y$ denotes the vertical direction,
$Y$ is the specific weight of the fluid ($= \rho g$),
The negative sign indicates that pressure decreases with upward movement.
A wooden cubical block of relative density 0.4 is floating in water. Side of cubical block is $10 \text{ cm}$. When a coin is placed on the block, it dips by $0.3 \text{ cm}$, weight of coin is: