APPLIED MECHANICS - Anna University Question Papers

[Kalyan]

APPLIED MECHANICS

Code: D-02

Time: 3 Hours Subject

Max. Marks: 100


NOTE: There are 11 Questions in all.

Question 1 is compulsory and carries 16 marks. Answer to Q. 1. must be written in the space provided for it in the answer book supplied and nowhere else.

Answer any THREE Questions each from Part I and Part II. Each of these questions carries 14 marks.
Any required data not explicitly given, may be suitably assumed and stated.

____________________Q.1 Choose the correct or best alternative in the following: (2x8)

a. In case of frictionless support

(A) the reactions acts normal to the surface at the point of contact.
(B) there is no reaction.
(C) the reaction acts tangential to the surface at the point contact.
(D) the reaction acts neither normal to the surface at the point of contact nor tangential to the surface at the point of contact.
b. For the equilibrium of a body subjected to two forces, both the forces must be

(A) equal in magnitude.
(C) both (A) & (B).
(B) opposite in direction.
(D) None of these.

Polar moment of inertia is

(A) equal to the product of Ixx & Iyy.
(B) equal to the sum of Ixx & Iyy.
(C) equal to the difference of Ixx & Iyy.
(D) None of the above Ixx & Iyy.
d. A stone is dropped into a well & the sound of the splash is heard after 4 seconds. Assuming velocity of sound to be 350 m/s, the depth of the well will be equal to

(A) 7.077 m
(C) 707.7 m. (B) 70.77 m.
(D) None of the above.

e. A motorist is travelling on a curved road of radius 200 m at a uniform speed of 72 Km/hour. The normal component of acceleration will be

(A) 2 m/s2.
(C) 0.2 m/s2. (B) 2.2 m/s2.
(D) None of the above.

f. To calculate shear stress while punching a hole of 'D' diameter in a plate of thickness 't' by a force 'F', the expression used is

g. The ratio of direct stress & direct strain within elastic limit is called
(A) modulus of rigidity.
(C) bulk modulus. (B) modulus of elasticity.
(D) None of the above.

h.In case of a cantilever loaded with a concentrated load at its free end, the maximum B.M. occurs at
(A) free end. (B) fixed end.
(C) mid span. (D) None of the above.

PART I

Answer any THREE Questions. Each question carries 14 marks.

Q.2
Determine the centroid of the cross sectional area of an unequal I-section as shown in Fig. 1.

Q.3Determine the axial forces in the bars of a plane truss loaded as shown in Fig. 2.

Q.4A screw jack has square threads of mean diameter of 10.0 cm & a pitch of 1.25 cm. Determine the force that must be applied to the end of 50 cm lever
(i) to raise a weight of 50 kN (ii) to lower a weight of 50 kN
Find the efficiency of the jack. Is it a self-locking jack ? Assume = 0.20. (14)

Q.5Two blocks of masses M1 & M2 are connected by a flexible but inextensible string as shown in Fig.3. Assuming coefficient of friction between & horizontal surface to be = 0.25. Find the acceleration of the masses & tension in the string. Assume M1 = 10 kg & M2 = 5 kg.

(14)Q.6 A car starts from rest on curved portion of road of radius 250 m & attains a speed of 18 km/hour at the end of 60 seconds while traveling with a uniform acceleration. Find the tangential & normal accelerations of the car 30 seconds after it started. (14)

PART II

Answer any THREE Questions. Each question carries 14 marks

Q.7

A cylinder of radius 1 m rolls without slipping along a horizontal plane AB. Its center has a uniform velocity of 20 m/s. Find the velocity of points E & F on the circumference of the cylinder as shown in Fig.4.

(14)Q.8 Draw the shear force and bending moment diagrams for the beam shown in Fig.5. Indicate the numerical value at all important sections in the diagrams.

Q.9A steel bar 25 mm diameter is loaded as shown in Fig.6. Determine the stresses in each part and the total elongation. E = 210 G Pa.(14)

Q.10Derive the following expression for a circular shaft of radius r and length .

Where T = Torque applied
J = Polar moment of inertia
G = Modulus of rigidity
= Angle of twist
= Length of shaft
= Shear stress
r = radius of shaft (14)

Q.11 Explain the following :

(i) Complementary shear stress.
(ii) Tensile stress strain curve for a ductile material.
(iii) Law of polygon of forces.
(iv) "General plane motion of a rigid body can be considered as the sum of
a plane translation & a rotation about an axis perpendicular to the plane motion." (14)