A block of wood is kept on a table top The mass of the wooden block is 5 kg and its dimensions are `40cmxx20cmxx10cm`. Find the pressure exerted by the wooden block on the table top if it is made to lie on the table with its sides of dimension (a)`20cmxx10cm`(b) `40cmxx20cm`. Given`g=9.8(m)/(s^2)`.

Explanation

(a) `F=mg=(5kg)xx(9.8(m)/(s^2))=49N`
`A_1=20cmxx10cm=200cm^2=200xx10^-4m^2`
`P_1=(F)/(A_1)=(49N)/(200xx10^-4m^2)=2450(N)/(m^2)=2450Pa`
(b) `A_2=40cmxx20cm=800cm^2=800xx10^-4m^2`
`P_2=(F)/(A_2)=(49N)/(800xx10^-4m^2)=612.5(N)/(m^2)=612.5Pa`