(Deemed to be University Established Under Section 3 of UGC Act 1956)
Pollachi Main Road, Eachanari Post, Coimbatore – 641 021. INDIA
Faculty of Engineering
Department of Aerospace Engineering
Subject code : 15BTAS204 /15BEAR205 Subject :ENGINEERING MECHANICS
Time : 2 Hours Maximum Marks : 60
Date:
PART – A (14X 1 = 14 Marks)
One mark Questions
1.
Moment = Force X _________ a) volume b) distance c) force
2.
The force causes _________ displacement
d) area a) linear b) angular c) distance d) moment
3.
A body will be in equilibrium, if the ________ in any direction is zero. a) angle b) displacement c) resultant force d) force
4.
The moment causes ____________ displacement a) angular b) linear c) moment d) displacement
5.
If the forces are acting in one plane, then the forces are called _________ a) coplanar forces b) collinear forces c) concurrent d) forces
6.
If the forces are intersecting at a common point, then the forces are called ________ a) concurrent forces b) coplanar c) collinear d) current forces
7.
If the forces are having same line of action, then the forces are called a) current forces b) collinear forces c) concurrent d) coplanar
8.
The resultant R of three (or) more forces acting at a point is given by, R = ________ a) √(ΣH)
2
+ (ΣV)
2 b) ΣH + ΣV c) ΣH + V d) H / V
9.
The ________ forces are parallel to each other & are acting in the same direction. a) unlike forces b) unlike parallel forces c) like parallel forces d) forces
10.
The ________ forces are acting in the opposite direction.
a) unlike parallel forces b) parallel forces c) like forces d) moment
11.
If the resultant of a no. of parallel forces is zero, then the system may have a
_________ a) resultant couple or may be in equilibrium b) moment c) couple d) force

12.
If the algebraic sum of moments of all forces about any point is not zero, then system will have a ____________
a) resultant couple b) moment c) force d) equilibrium
13.
If the algebraic sum of moments of all forces about any point is zero, then system will have a _________ a) equilibrium b) constant c) angular displacement d) linear
14.
The study of a body in motion, when the forces which cause the motion are not considered, is called _________ a) kinematics b) dynamics c) scalar d) kinetics
15.
The study of a body in motion, when the forces which cause the motion are considered, is called ________ a) kinematics b) dynamics c) scalar
16.
Lame's theorem= ___________ a)
(P/sinα) = ( Q/sin β) = (R/sinγ) c) (P/cos α) = ( Q / cos β) = (R / cos γ) d) kinetics b) P=Q=R d) P = Q =R = sin α
17.
Unit for moment of force is _________________
a) N b) m c) N-m d) m
2
18.
Unit for work (or) energy _____________ a) joule b) N-m c) N d) second
19.
Unit vector = ________________ a) F/ √(Fx 2 + Fy 2 + Fz 2 ) b) √(Fx 2 + Fy 2 + Fz 2 ) c) F/ (Fx 2 + Fy 2 + Fz 2 ) d) F
20.
If two forces are acting on a particle, the particle will be in equilibrium, when the two forces are equal, _________ & ________ a) Opposite & collinear b) Concurrent c) collinear d) Opposite & concurrent
21.
If three forces are acting on a particle, the particle will be in equilibrium, when the three forces are ________ a) collinear b) Concurrent c) parallel d) forces
22.
unit for acceleration = _____________ a) m/s
2 b) m.s
2 c) m.s
23.
Which of the following is a scalar quantity? d)m a) Force b) Speed c) Velocity d) Acceleration
24.
The forces, which meet at one point and their lines of action also lie on the same plane, are known as a) coplaner concurrent forces b) coplaner non-concurrent forces

c) non-coplaner concurrent forces d) non-coplaner non-concurrent forces
25.
The unit of force in S.I. system of units is a) dyne b) kilogram c) Newton d) watt
26.
If the resultant of two equal forces has the same magnitude as either of the forces, then the angle between the two forces is a) 30° b) 60° c) 90° d) 120°
27.
The angle between two forces when the resultant is maximum and minimum respectively are d) 90° and 0° a) 0° and 180° b) 180° and 0°
28.
The unit of power in S.I. units is a) Newton meter b) Watt c) 90° and 180° c) Joule d) Pascal
PART – B (3 X 12 = 36 Marks)
15.
a) Five forces act on a bolt `B` as shown in figure. Determine the resultant of the forces on the bolt. (7) b) Determine the resultant of three forces 𝐹
1
= 2.0 𝑖 + 3.3 𝑗 - 2.6
⃗
,
⃗⃗⃗
= 𝑖 + 5.2 𝑗 -2.9
⃗ and 𝐹 = 8.3 𝑖 + -6.6 𝑗 +5.8 𝑘 ,which are concurrent at the point (2,2,-5). The forces are in
Newton and distances are in meters.
16.
a) Determine the magnitude and angle `θ` of F so that particle P shown in figure, it is in equilibrium.

b) Three concurrent forces F
1
, F
2 and F
3 are acting at A as shown in fig. An unknown force F attached to the system makes the particle A in equilibrium. Find the magnitude and direction of the unknown force .
17.
a) A simply supported beam AB of 6 m span is loaded as shown. Point A is a hinged support Point B is a roller support .Determine the reactions at A and B.
b) Determine the reaction forces acting at points A and B as shown in figure.

18. a) ABCDE is a light string whose end A is fixed. The weights W
1
and W
2
are attached to the string at B and C and the string passes round a small smooth wheel at D carrying
40KN at the free end E. In the position of equilibrium, BC is horizontal and AB and CD make angles 150
0
and 120
0
with horizontal. Find (i) The tensions in AB, BC and DE of the given string. (ii) The magnitude of W
1
and W
2
. b) Three concurrent forces F
1
, F
2 and F
3 are acting at A as shown in fig. An unknown force
F attached to the system makes the particle A in equilibrium. Find the magnitude and direction of the unknown force .
19. a) i) A force 𝐹 = 6 𝑖 - 3 𝑗 -4 𝑘 . Is acting at a point P whose position vector from the origin ‘O’ of the co-ordinate axes is 𝑟 = 8 𝑖 + 6 𝑗 -4 𝑘 .Find the moment of the force about the origin. (6) ii) Three couples +12 Nm, -35Nm and +100Nm are acting in the xy, yz and xz. Write the vector form. (6)
b)The figure shows three cables AB,AC, AD that are used to support the end of a sign which exerts a force of 𝐹 = {250 𝑖 + 450 𝑗 − 150 𝑘 } N at A. Determine the force developed in each cable.

20.a) Determine the resultant of three forces 𝐹 = 2.0 𝑖 + 3.3 𝑗 - 2.6 𝑘⃗ , 𝐹 = 𝑖 + 5.2 𝑗 -2.9
𝑘⃗ and 𝐹
= 8.3 𝑖 + -6.6 𝑗 +5.8 𝑘⃗ ,which are concurrent at the point (2,2,-5). The forces are in Newton and distances are in meters.
b) Determine the reactions at the supports A and E for the beam shown in the fig.