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PAGES: 4 2571Reg.No.:(c)http://www.reelxstudios.thrikkunnapuzha.comName:(c)http://www.reelxstudios.thrikkunnapuzha.com

Combined First and Second Semester B.Tech. Degree Examination, May 2009

(2008 Scheme)

08 -105 : ENGINEERING MECHANICS

Time : 3 Hours Max. Marks : 100

PART - A

Answer all questions under Part A. Each carries 5 marks.1. State the Varignon's principle and differentiate between moment of a force and a

couple.

2. A simply supported beam AB is subjected to a distributed load increasing from1500 N/m to 4500 N/m from end A to end B. Span AB = 6 m . Determine thesupport reactions.

3. Prove that the angle of friction is equal to the angle made by an inclined plane with

the horizontal when a rigid body which is placed on the inclined plane is about to

slide downwards.

4. Explain the theorems of Pappus - Guldinus.

5.Explain instantaneous centre of rotation. How can it be located for a body movingwith combined motion of rotation ?

6. Prove that the lowest point in touch with the ground of a wheel rotating without

slipping is the instantaneous centre of the motion of the wheel.

7. Explain D'Alembert's principle applicable to curvilinear motion.

8. Explain the terms angular momentum, angular impulse and torque.

P.T.O.

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PART-B

Answer any two questions from each Module. Each carries 10 marks.

Module - 11. Two rollers weighing 6 kN and 3 kN supported on an inclined plane are connected

by a string as shown in figure. Find the angle 0(theta) that makes with horizontal so that

the system is in equilibrium.

2. a) Define cantilever and overhanging beam.

b) A bar of 6 m length with negligible weight rest in a horizontal position on the

smooth planes as shown in figure. Determine the load P and reactions at supports.

3. A wedge 'A' has to be driven for tightening a body B loaded with 2000 N weight as

shown in figure. If the coefficient of friction for all surfaces is 0.25, find the force Pwhich should be applied to the wedge.

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Module - II

1 a) Locate the centroid of a right angled triangular section with height ' h ' and base'b' by method of integration.

b)Cross section of a culvert is shown in figure. Calculate the moment of inertia of

shaded region about the horizontal axis AA.Qc*f>

2.A cylinder of radius 1 m rolls without slipping along a horizontal plane AB. Its

^ centre has uniform velocity of 25 m/s. Find the velocity at points C and D on thecircumference of the cylinder is shown in figure.

3. Find : (i) Acceleration of the masses and (ii) tension in the strings acting on a

system of weights shown in figure. Coefficient of friction for the contact surfaces

of bodies A and B are 0.4.

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