A block of wood of mass 6kg and dimensions `50cm xx 30cm xx 10cm` is placed on a table top. Find the pressure exerted, if the block lies on the table top with sides of dimensions, (a) `50cm xx 30cm` (b) `30 cm xx 10cm`.

Answer

(a) `392 Nm^(-2)` (b) `1960Nm^(-2)`

Explanation

Here, the mass of wooden block =6kg, dimensions `50cm xx 30 cm xx 10cm`.
Thrust `F=mg =6kg xx 9.8ms^(-2)=58.8N`
(a) Area of the side `=50cm xx 30cm `
`=(50)/(100)m xx (30)/(100)m`
`=0.15 m^(2)`
Pressure `=("Thrust")/("Area")`
`=(58.8N)/(0.15m^(2))=392N m^(-2)`
(b) Area of the side `=30 cm xx 10cm`
`=(30)/(100)m xx (10)/(100)m`
`=0.03m^(2)`
Pressure `=("Thrust")/("Area")=(58.8N)/(0.03 m^(2))=1960Nm^(-2)`