Multiple Choice

Three identical blocks each of mass $$m\ =\ 1\ kg$$ and volume $$3\ \times \ { 10 }^{ -4 }\ { m }^{ 3 }$$ are suspended by massless string from a support as shown. Underneath are three identical containers containing the same amount of water that are placed over the scales. In Fig.4222 (a), the block is completely out of the water; in Fig. 4.222(b), the block in completely submerged but not touching the beaker and in Fig. 4.222(c), the block rests on the bottom of the beaker. The scale in Fig. 4.222(a). The scale in Fig. 4.222(a) reads $$14\ N$$.

AThe tension in the string in (b) is $$10\ N$$
BThe tension in the string in (b) is $$7\ N$$
Correct Answer
CThe reading of the scale in (b) is $$17\ N$$
Correct Answer
DThe reading of the scale in (c) is $$24\ N$$
Correct Answer

Solution

$$\text { In figure (b), buoyant acting on the block }=V pg \\$$
$$ =3 \times 10^{-4} \times 10^{3} \times 10 \mathrm{~N} \\$$
$$ =3 \mathrm{~N}$$

Forces acting on the block balance, thus
$$m g=B+T \\$$
$$\Rightarrow T=m g-B=(10-3) N \\$$
$$ =7 N$$



SIMILAR QUESTIONS

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Laws of Motion

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