A rectangular wooden block has mass of 4 kg .The length ,breadth and height of this wooden block are 50 cm,25 cm and 10 cm ,respectively .Find the pressure on the table top:
( a) When the wooden bock is kept with its surface measuring `50 cm xx 25 cm` on the table .
(b) When the wooden block is kept with its sufarce measring `25 cm xx 10 cm ` on the table . (Assume : Acceleration due to gravity ,` (g=10 m/s^(2))`

Explanation

Here Mass of wooden block m= 4kg
Acceleration dur to gravity ,`g=10 m//s^(2)`
Weight of wooden block ` W=mxxg `
`=4xx10`
=40 N
since weight is a force,so we can say that the force excerted by the wooden block on the table top is 40 N .We will now calculate the pressure in the two cases.

(a) In the first case : Force = 40 N (Calculated above)
`Area =50 cm xx 25 cm`
`=(50)/(100) m xx (25)/ (100 )`
`=0.5 m xx 0.25 m`
` = 0.125 m^(2)`
Now Pressure ` =("Force")/("Area")`
`=40/0.125`
`=320 Nm^(2)` (or 320)
Thus the pressure exerted by the wooden block on table top when kept on its face measuring `50 cm xx 25 cm ` is 320 `Nm^(-2)` of 320 pascals (see Figure 44)
(b) In the second case : Force = 40 N (Same as above)
Area `= 25 cm xx 10 cm`
`=25 /100 mxx10/100 m`
`=0.25 m xx 0.1 m`
`=0.025 m^(2)`
`Pressre = (Force)/(Area)`
`=(40)/(0.025)`
` =1600 N m^(-2)` (or 1600)
Thus the pressure exerted by the wooden block on table top when kept on its face measuring `25 cm xx 10 cm ` is 1600 N `m^(-2)` of 1600 pascals (see figure 45)