Data : 1 = 10 cm, b = 5 cm,
h = 2 cm, p= 8 × 10 kg/m3, g = 9.8 m/s2 ,
A = lb = 10cm × 5cm = 50cm2 = 50 × 104m2
= 5 × 10-5 m2 , force =?, pressure = ?
Volume of the block = lbh = 10 cm × 5 cm × 2 cm
= 100 cm3 = 100 × 10-6 m3 = 1 × 10-4 m3
Mass of the block = volume × density
(∵ density = mass/volume)
∴Mass of the block,
m = 1 × 10-4 m3 × 8 × 103 kg/m3 = 0.8 kg
Weight of the block = mg = 0.8 kg × 9.8 m/s2 = 7.84 N
∴ The force exerted by the block on the table = 7.84 N.
force 7.84 N
Pressure = \(\cfrac{force}{area}\) = \(\cfrac{7.84N}{5\times10^{-3}\,m^2}\)
= 1.568 × 103 N/m2 or 1.568 × 103 Pa
The pressure exerted by the block on the table
= 1.568 × 10 N/m2 or 1.568 × 103 Pa.