Question 128: Properties of Matter

Question

A uniform heavy rod of weight 10 kg ms
$$-$$2
, cross-sectional area 100 cm
2
and length 20 cm is hanging from a fixed support. Young modulus of the material of the rod is 2 $$	imes$$ 10
11
Nm
$$-$$2
. Neglecting the lateral contraction, find the elongation of rod due to its own weight.

Accepted Answer

We know,
$$\Delta l = {{WL} \over {2AY}}$$
$$\Delta l = {{10 	imes 1} \over {2 	imes 5}} 	imes 100 	imes {10^{ - 4}} 	imes 2 	imes {10^{11}}$$
$$\Delta l = {1 \over 2} 	imes {10^{ - 9}} = 5 	imes {10^{ - 10}}$$ m
Option (d)

Answer

2 $$	imes$$ 10
$$-$$9
m

Answer

5 $$	imes$$ 10
$$-$$8
m

Answer

4 $$	imes$$ 10
$$-$$8
m

Answer

5 $$	imes$$ 10
$$-$$10
m

Properties of Matter

A uniform heavy rod of weight 10 kg ms $-2 , cross-sectional area 100 cm 2 and length 20 cm is hanging from a fixed support. Young modulus of the material of the rod is 2 \times 10 11 Nm -$2 . Neglecting the lateral contraction, find the elongation of rod due to its own weight.

Choose the correct answer: