Question

A Rectangular block side 5cm heights*10cm*20cm is made material of density 2.5g/cm^3. Find the maximum pressure it can exert when resting with one of it face on a horizontal surface.

Answer 1

The minimum and maximum pressure a block can exert is 3000 Pa and 15000 Pa and thrust in both the cases is 60N.

Explanation:

Volume Of the given block:

Volume  = 4×10×20 cm = 800 cm³

Mass of the block:

mass = volume x density

= 800 * 7.5

= 6000 gm or 6 kg

Weight of the block, W:

W = mg

= 6 * 10

= 60N

But, Thrust  =  weight { ∵ A block is at equilibrium. thus, net force = 0  }

Therefore, thrust in both the cases = 60N

Pressure exerted by the block:

Pressure (P) = Thrust / face area

=> Maximum pressure:

Pmax = W/Amin = 60/(4x10x10⁻⁴) = 15000 Pa

=> Minimum Pressure:

PMin =  W/Amax = 60/(20x10x10⁻⁴) = 3000 Pa

Hence, The minimum and maximum pressure a block can exert is 3000 Pa and 15000 Pa.