SKR Engineering College 2007 B.E Mechanical Engineering GE-1151-ENGINEERING MECHANICS - Question Paper

S.K.R ENGINEERING COLLEGE
POONAMALLEE ,CHENNAI-602301
Second Semester
(Regulation 2004)
GE-1151-ENGINEERING MECHANICS
Time: 3 hours Maximum:100 marks
ans ALL ques.

PART-A (10x2=20)

1. A force F = 700 i +1500 j is applied to a bolt A. Determine the magnitude of the
force and the angle it forms with the horizontal.
2. Define Principle of transmissibility.
3. State Varignon’s theorem.
4. State perpendicular axis theorem.
5. describe principle axes and principle moment of inertia
6. What is called coefficient of static friction?
7. State D’Alembert’s principle
8. What is general plane motion?
9. Define co-efficient of restitution.
10. State legal regulations of conservation of momentum.

PART-A (5x16=80)

11. (i) A system of 4 forces acting on a body is as shown in fig (i). Determine the
resulting force and its direction. (8)

(ii) A smooth circular cylinder of radius 1.5m is kept in a triangular groove, 1 side of which makes 450 and other 300 with horizontal. obtain the reactions at the surface of contact. If there is no friction and the cylinder weight is 100kg. (8)

12. (a) (i) A plate is acted upon by 3- forces and two couples as shown in
fig(2).Determine the resulting of these force couple system and obtain coordinate x of the point on the x- Axis through which the resulting passes (8)

(ii) A load P of 3500 N is acting on the boom, which is held by cable BC
as shown in fig (iii).The weight of the boom can be neglected (a) Draw the free body
diagrams of the boom.(b) obtain the tension in cable BC
(c) Determine the reaction of A. (8)
OR
(b) A tension T of magnitude 10 kN is applied to the cable attached to the top A
of rigid mast and secured to the ground at B as shown in fig (4). Determine moment of
the tension T about the z-axis passing through the base O. (16)




13. (a) Determine the centroidal co ordinates of the area shown in fig (5) with respect to the Shown x-y co ordinate system. (16)
OR

(b) Determine the moments of inertia of beam’s cross-sectional area shown in
fig (6) about x about y centroidal axes. (16)

14. (a) (i) 2 stations P and Q are 5.2 Km apart. A train begins from rest at the station P and accelerates uniformly to attain a speed of 54Km/h in 30 seconds. The speed is maintained until the brakes are applied. The train comes to rest at the station Q with uniform retardation of 1m/s2. Determine the total time needed to cover the distance ranging from these 2 stations. (8)
(ii) A body is projected at an angle such that its horizontal range is three times
the maximum height. obtain the angle of projection. (8)
OR
(b) (i) 2 blocks of mass 20 kg and 40 kg are connected by a rope passing over a frictionless pulley as shown in fig (7). presume the coefficient of friction as 0.3 for all contact surfaces. obtain the tension in the string, and the acceleration of the system. Also calculate the velocity of the system after four seconds starting from rest. (8)

(ii) In fig (8) shown 2 masses A and B are connected by a rope and pulley. The masses are released from rest. Assuming pulleys are frictionless and weightless, determine (i) Tension of the rope.
(ii) acceleration masses A and B. (8)

15. (a) Determine the smallest force P needed to move the block B shown in fig(9).If (i) block A is restrained by cable CD (ii) cable CD is removed. Take ms = 0.30 and mk= 0.25. (16)

OR
(b) (i) A screw jack has square threads of mean dia.of 10cm and pitch 1.25cm.
Determine the force that must be applied to the end of 50 cm lever (i) to raise
(ii) to lower a weight of 50kN, obtain the efficiency of jack. Is it self-locking?
Assumem=0.2 (8)

(ii) 4 turns of rope around a horizontal post will hold a 450kg mass with a
pull of 45N .Determine the coefficient of friction ranging from the rope and the post .(8)

Earning:   Approval pending.