$3. A rec\tan gular solid block has sides 4\times 10\times 20 cm and a density of 7.5 g c{m}^{-1}.if it rests on a horizontal flat surface calculate the minimum and maximum pressure it can exert\left(in SI units\right) . Also calculate the thrust in both cases. \left(Ans: 3000 Pa and 15000 Pa , 60 N\right)$

Dear Student
Volume Of the block = 4*10*20 = 800 cm³
Mass of the block m = volume * density = 800 * 7.5 = 6000 gm = 6 kg
Weight of the block W = mg = 6 * 10 = 60N
Thrust by the surface should be equal to the weight because it is at equilibrium so net force should be zero.
Therefore thrust in both the cases = 60N

Pressure exerted by the block  P = Thrust / face area
Maximum pressure P_max = W/A_min = 60/(4*10*10^-4) = 15000 Pa
Minimum Pressure P_Min =  W/A_max = 60/(20*10*10^-4) = 3000 Pa

I hope the solution is helpful.
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