Question

The area of cross section of the wider tube shown in figure is 900 cm2. If the boy standing on the piston weighs 45 kg, find the difference in the levels of water in the two tubes.
Figure

Answer 1

Explanation:

point are very poor as answer please give 50 points

Answer 2

Difference in the levels of water in the two tubes = 50cm.

Explanation:

• Area of wider tube (A) = 900cm2  

• Weight of the boy (m) = 45kg

• Difference in the levels of water in the two tubes (h)= ?

• As per Pascal’s law, even though the left side tube area is smaller than the right side tube area, the pressure is transmitted equally in all directions through the liquid.

Hence,  

• P0   + F/A = P0 +  ρhg  
• [P0 = Atmospheric pressure  
• ρ = density of water = 1000 kg/m3
• g = gravitational field strength = 10ms-²]
• ⟹ F/A = ρhg
• ⟹ mg/A = ρhg
• ⟹ m/A = ρh
• ⟹ h = m/(A ×  ρ)
• ⟹ h= 45/ ( 900 ×  10-4 ×  1000) = 1/2
• ⟹  h=0.5 m =50 cm