(Paper) Engineering Mechanics, May-2001(MG University)

MG University
B. Tech Degree Examination, May 2001
First and Second Semester

Engineering Mechanics
(Common for all branches)


Time: Three Hours                                                                                               Maximum : 100 Marks

Answer all questions Each questions carry 4 marks

Part A


Define force. Explain the characteristics of force.


Explain free body diagram.


Define centroid and second moment of area of a composite section.


Define friction and state the laws of friction.


Distinguish between linear velocity and angular velocity. Derive the relation.


Distinguish between translation and rotational motion.


Distinguish between kinetics and kinematics.


Explain the D’Alemberts principle of rotation.


Explain the principle of analysis of trusses by method of joints.


State and explain Hook's law.

(10 x4 = 40 marks)

Part B

Answer (a)
or (b)
Each question carry 12 marks


a) State and explain Lami’s theorem. Three forces OA, OB and OC acting at apoint O such that angle AOB = 100 degrees. Force OA and OB are pulling the point O with forces 120 KN and 80 KN respectively. Find the magnitude and direction of the force OC to keep the point O in equilibrium.


b) A simply supported beam AB supported at A and B and having span 4 M carries three loads 4 KN, 8 KN and 5 KN at distances 1 M, 2M and 3 M from A. Sketch the beam and determine the reactions at A and B.


a) An I-section have the following dimensions. Top flange width and bottom flange width 120mm. Depth of the web 180mm. Total depth of I-section 200 mm. Thickness of web and flanges 10 mm. Sketch the section and determine the area moment on inertia about XX and YY axis.


b) A body weighing 2 KN has to rest on an inclined plane. The angle of limiting friction is 15 degrees, while the angle of the plane is 20 degrees. Find the least and the greatest force that can be applied on the body, parallel to the plane so as to keep the body in equilibrium.


a) A wheel starting from rest is accelerated at the rate of 5 radians per sec for an interval of 10 sec. If it is then made to stop in next 5 sec by applying brakes, determine
(i) The maximum velocity attained; (ii) Total angle turned.


b) The pilot of an aero plane flying horizontally with a constant speed of 480 km/hr at an elevation of 600 M from level ground wishes to bomb a target R on the ground. At what angle below the horizontal should he see the target at the instant of releasing the bomb in order to score a hit? Neglect air resistance.


a) A body weighing 40 N drops freely from a height of 50M and penetrates in to the ground by 100 cm. Find the average resistance to penetration and the time of penetration.


b) A body of mass 20kg slides down on a rough inclined plane whose inclination to the horizontal is 30 degrees. If the coefficient of friction is 0.4 determine the acceleration.


a) A triangular steel truss ABC supported at A and B carries a concentrated load 10 KN at C. The length of all the members are 4 M and area of cross-section 10 square cm. Determine the stresses in all the members.


b) A wooden tie 6 M long 750 mm wide and 100 mm thick is subjected to an axial pull of 45 KN and the stretch is 3.85 mm. Calculate the value of Young's modulus of elasticity.

(5 x 12 = 60 marks)