Question

A bottle is filled with water. A cap is put on the bottle and it is turned upside down. There is no air inside the bottle. The area of the cap in contact with the water is $4.0\times {10}^{-4}{m}^2$. The density of water is $1000kg{m}^{-3}$ and the gravitational field strength is $10Nk{g}^{-1}$. The water produces a force on the cap.What is the value of this force?

• A. $0.075N$
• B. $0.12N$
• C. $1.2N$
• D. $13N$

Answer 1

Answer: (C)

$1.2N$

Density $\rho =1000kg/m^3$

Height $h=0.3m$

$g=10Nk{g}^{-1}$

Area $A=4\times {10}^{-4}$

$F=PA;P=\rho gh=1000\times 10\times 0.3=3000$

$F=3000\times 4\times {10}^{-4}=1.2N$