Question
Question: A tank of base area 4 m<sup>2</sup> is initially filled with water up to height 2 m. An object of un...
A tank of base area 4 m2 is initially filled with water up to height 2 m. An object of uniform cross-section 2 m2 and height 1 m is now suspended by wire into the tank, keeping distance between base of tank and that of object 1 m. Density of the object is 2000kg/m3. Take atmospheric pressure 1 × 105N/m2; g = 10 m/s2
The downward force exerted by the water on the top surface of the object is:
A
2.0 × 105N
B
2.1 × l05N
C
2.2 × 105N
D
2:3 × l05N
Answer
2.1 × l05N
Explanation
Solution
By conservation of volume 4 × h = 4 × 2 + 2 × 1 = 10
h = 2.5m
Pressure at top of the object = P0 + 0.5 × 1000 × 10
= 1.05 × 105N/m2 F = P1A
= 1.05 × 105 × 2 = 2.1 × 105N