An iron cylindar of base area `7 cm^2` and mass 10 kg is melted and reshaped into a into a rod of area of cross section `1cm^2`.Calculate the increase in the pressure exerted on a plane surface when both the cylinder and the rod are made to stand vertically on a plane surface `(g= 10m^(-2))`
A
`100xx10^(4)` Pa
B
`10xx10^(4)` Pa
C
`14.28xx10^(4)` Pa
D
`85.72xx10^(4)` Pa
Text Solution
Verified by Experts
The correct Answer is:
D
Given, mass of cylinder, `m_(c)=10" kg"` Base area of the cylinder, `A_(c)=" 7 cm"^(2)=7xx(10^(-2))^(2)=7xx10^(-4)m^(2)` Pressure due to cylinder. `P_(c)=(F_(c))/(A_(c))=(m_(c)g)/(A_(c))=(10xx10)/(7xx10^(-4))=14.28xx10^(4)" Pa"` Mass of the rod, `m_(r)=10" kg"` Base area of the rod, `A_(r)1" cm"^(2)=1xx(10^(-2))^(2)=10^(-4)m^(2)` Pressure due to rod. `p_(r)=(F_(r))/(A_(r))=(m_(r)g)/(A_(r))=(10xx10)/(10^(-4))=100xx100^(4)" Pa"` Increase in pressure, `P_(r)-P_(c)=(100-14.28)xx10^(4)" Pa"` Hence, the correct option is (d).
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