Download Sathyabama University B.E June 2011

Register Number
SATHYABAMA UNIVERSITY
(Established under section 3 of UGC Act,1956)
Course & Branch :B.E - AERO/AUTO/CIVIL/M&P/MECH
Title of the Paper :Engineering Mechanics
Max. Marks :80
Sub. Code :5ET109-6C0010
Time : 3 Hours
Date :01/06/2011
Session :AN
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1.
PART - A
(10 x 2 = 20)
Answer ALL the Questions
What are equations of static equilibrium?
2.
State Varignon’s theorem of moments.
3.
Locate the centroid of a semicircle.
4.
State – Routh’s rule.
5.
Define – Angle of respose.
6.
List the characteristics of dry friction.
7.
State Newton’s second law of motion.
8.
Define – Uniform accelerated motion.
9.
Define – Rigid body.
10. State D’Alemberts principle.
PART - B
(5 X 12 = 60)
Answer ALL the Questions
11. Calculate the resultant of the following four concurrent forces
acting away from the point ‘O’
(a) 60 N towards East
(b) 40 N towards 20 East to North
(c) 33 N towards 30 West to North
(d) 22 N towards 50 West to South
(or)
12. A circular roller of radius 20cm and weight of 400N rests on a
smooth horizontal surface and is held in a position by an inclined
bar AB of length 60cm as shown in the figure. A horizontal force
of 500N is acting at B. Find the tension in the bar AB and the
reaction at C.
13. Determine the centroid of the section shown in the figure
(or)
14. Find the moment of inertia of the channel shown in the figure
about its centroidal axis X and centroidal axis Y. And also find
the polar moment of inertia.
15. A ladder 5m long and 250N weight is placed against a vertical
wall in a position where it’s inclination to the vertical is 30. A
man weighing 800N climbs the ladder. At what position, will he
induce slipping? Take  = 0.2 for all cases.
(or)
16. An effort of 18N is required to move a body up in the inclined
plane at an angle of 15. If the angle is changed to 20, the effort
needed is 21N. In both the cases, the force is parallel to the plane.
Find out the weight of the body and coefficient of friction.
17. A motar car takes 10 seconds to cover 20m and another 15
seconds to cover another 40m distance. Find the initial velocity
and constant acceleration. Also determine the velocity at the end
of 15 seconds.
(or)
18. A bullet of mass 25 gram is moving with a velocity of 500 m/sec
and fired into a body of 12Kg, which is suspended by a string,
fixed at top 1m long. The bullet gets embedded into the body and
the unit (ie bullet + body) swings through some angle. Find out
the angle through which the unit swings.
19. A fly wheel 0.5m in diameter is brought uniformly from rest up
to a speed of 280 rpm in 20 seconds. Find the velocity and
acceleration of a point on the rim at 2 sec after starting from rest.
(or)
20. A truck weighing 4T is moving up in a 30 plane. If the truck
moves at a steady speed of 20 Km/Hr and coefficient of friction
between truck tyres and the plane is 0.2. Determine how much
power is needed to move the body.