### Strength of Materials (Stresses and Strains)

Q.1. A bar of diameter 30 mm is subjected to a tensile load such
that the measured extension on a gauge length of 200 mm is 0.09 mm and the change
in diameter is 0.0045 mm. The Poisson’s ratio will be

(a) 1/4

(b) 1/3

(c) 1/4.5

(d) 1/2 (IES
1995)

Q.2. A steel cube of volume 8000 cc is subjected to all round stress
of 1330 kg/sq.cm. The volumetric change is

(a) 8 cc

(b) 6 cc

(c) 0.8 cc

(d) 0.01 cc (IES
1995)

Q.3. A steel tube is surrounding a solid aluminium cylinder. A force
P is applied at the assembly. The aluminium cylinder is 75 mm in diameter and
outside diameter of the steel tube is 90 mm. Given E

_{steel}= 200 GNm^{-2}and E_{aluminium}=25 GNm^{-2}If P = 200 kN, the stress in steel tube will be
(a) 10 MPa

(b) 60.75 MPa

(c) 80.25 MPa

(d) 100 MPa

Q.4. In the above problem, stress in aluminium will be

(a) 10 Mpa

(b) 60.75 MPa

(c) 80.25 MPa

(d) 100 MPa

Q.5. A bar of length L is fitted between two supports and the
temperature is increased t

^{0}. If support does not yield, the temperature stress in the bar will be
(a) 0

(b) tE

(c) at

(d) atE

Q.6. The length, coefficient of thermal expansion and Young’s
modulus of bar A are twice that of bar B. If the temperature of both bars is
increased by the same amount while preventing any expansion, then the ratio of
stress developed in bar A to that in bar B will be

(a) 2

(b) 4

(c) 8

(d) 16 (IES
1996)

Q.7. A steel bar, 300 mm long and 24 mm diameter, is turned down to
18 mm diameter for one third of its length. It is heated 30

^{0}C above room temperature, clamped at both ends and then allowed to cool to room temperature. If the distance between the clamped is unchanged, the maximum stress in the bar(a = 12.5 x 10^{-6}per^{0}C and E = 200 GN/m^{2}) is
(a) 25 MN/m

^{2}
(b) 50 MN/m

^{2}
(c) 75 MN/m

^{2}
(d) 100 MN/m

^{2}(IES 2000)
Q.8. A railway track is laid so that there is no stress in the rails
at 10

^{0}C. If there is no allowance for expansion then stress in the rails at 60^{0}C will be
(a) 53.3 N/mm

^{2}
(b) 110.7 N/mm

^{2}
(c) 115 N/mm

^{2}
(d) 120 N/mm

^{2}
Q.9. In the above problem if there is an expansion allowance of 10
mm per rail then stress in the rails at 60

^{0}will be
(a) 53.3 N/mm

^{2}
(b) 110.7 N/mm

^{2}
(c) 115 N/mm

^{2}
(d) 120 N/mm

^{2}^{}

Q.10. In the above problem what will be expansion allowance if stress
induced is zero

(a) 1 mm

(b) 7 mm

(c) 11 mm

(d) 18 mm

**Answers:**

1. b

2. a

3. c

4. a

5. d

6. b

7. d

8. d

9. a

10. d