An object weighs 30N in air and 21N in water. The weight of the object when completely immersed in a liquid of relative density 1.4 is
-
A.
25.2N -
B.
17.4N -
C.
12.6N -
D.
9.0N
Correct Answer: Option B
Explanation
Weight of water displaced = upthrust = 30 – 21 = 9N
Mass of water displaced = (frac{9}{10}) = 0.9kg
Volume of object = 9 × 10(^{-4})m(^3)
= (9 × 10(^{-4})) (1.4 ×103)
= 1.26kg = 12N
30 – 12.6 = 17.4N
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