Questions
ENGINEERING MECHANICS : OBJECTIVE QUESTIONS - UNIT I
A
Triangle law of forces states that if two forces
Third side of the
acting at a point are represented in
1 magnitude and direction by the two sides of
triangle taken in
the same order.
the triangle taken in order, then their
resultant is given by the
B
C
Third side of the
Sum of the two
triangle taken in the
forces acting.
opposite order
D
None of the
above.
third side of the
sum of the two
triangle taken in
forces acting.
the opposite order
none of the
above.
3 Law of polygon of forces states that
if a number of
forces acting at a
point are
represented by the
sides of a polygon
taken in order,
if a number of
forces acting at a
point are
represented by the
sides of a polygon
taken in order,
the resultant of a
number of forces
none of the
acting on a point
above.
is the sum of all
forces.
Two forces P and Q are acting at an angle θ,
4
their resultant R is given by,
R = √P2+Q2+2PQ
sin2 θ
R=
R = √P2+Q22
2
√P +Q +2PQcos θ 2PQcos θ
R=
√P2+Q2+2PQ
cos2 θ
tan α = Bsin
θ/(B+Acos θ)
tan α = Asin
θ/(A+Bcos θ)
tan α = Bcos
θ/(B+Acos θ)
2
third side of the triangle taken in the same
order.
Two forces A and B are acting at an angle θ
5 and their resultant R makes an angle α with
the force A, then
6
7
8
9
10
11
Lami’s theorem states that if
The forces which do not meet at appoint are
called
The forces whose lines of action do not lie in
the same plane, are called
The forces, whose line of action lie on the
same line, are known as,
The forces whose line of action does not lie
in the same plane but are meeting at one point,
are known as
The forces, whose line of action lie in the
same plane and are meeting at one poiunt, are
known as
tan α = Bsin
θ/(A+Bcos θ)
the three forces
three forces acting acting at a point can
at a point are in
be represented in
equilibrium, they magnitude and
can be represented direction by the
by the three sides sides of a tringle,
of a tringle
the forces are in
equilibriu,
three forces
acting at appoint
are in
equilibrium, each
none of the
force is
above
proportional to
the sine of
theangle between
the other two
non-coplanar
forces
non-coplanar
forces
non-concurrent
forces
non-concurrent
forces
coplanar forces
coplanar forces
concurrent
forces.
none of the
above
none of the
above.
coplanar forces
concurrent forces
collinear forces
coplanar
concurrent forces
non-coplanar
concurrent forces
non-coplanar non- none of the
concurrent forces above.
coplanar
concurrent forces
coplanar nonconcurrent forces
non-coplanar non- none of the
concurrent forces above.
12
lie in the same
plane and pass
through the same
point
Coplanar concurrent forces means the lines of lie in the same
plane
action of forces
do not lie in the
same plane
do not pass
through the
same point
The term force may be defined as an agent
13 which produces or tends to produce, destroys
agree
disagree
or tends to destroy motion
14 A force while acting on a body may
15
In order to determine the effects of a force,
acting on a body, we must know
16 The unit of force in S.I. system of units is,
magnitude of the
force
give rise to the
balance the forces,
internal stresses
already acting on it
in it
line of action of the nature of the
force
force
dyne
kilogram
true
false
composition
resolution
principle of
independence of
forces
principle of
principle of
transimissibility
resolution of forces
of forces
correct
incorrect
P+Q
P-Q
P/Q
Q/P
2Psin(θ/2)
2Pcos(θ/2)
2Ptan(θ/2)
2Pcot(θ/2)
0 and 180
180 and 0
90 and 180
90 and 0
p√2
P/2
P/2√2
√2P
change its motion
all of these
all of the above
Newton
watt
addition
multiplication
A resultant force is a single force which
17 produces the same effect as produced by all
18
19
20
21
22
23
24
25
26
the given forces acting on a body
The process of finding out the resultant force
is known as,
The algebric sum of the resolved parts of a
number of forces in a given direction is equal
to the tresolved part of their resultant in the
same direction. This is known as,
Vectors method for the resultant force is also
called polygon law of forces.
The resultant of two forces P and Q (P>Q)
acting along the same straight line, but in
opposite direction, is given by
The resultant of two equal forces P making
an angle θ, is given by
The angle between two equal forces when
the resultant is maximum and minimum
respectively are
The resultant of two equal forces P acting at
right angles is
If the resultant of two equal forces has the
same magnitude as either of the forces, then
the angle between the two forces is
The resultant of the two forces P and Q is R.
If Q is doubled, the new resultant is
perpendicular to P. Then
30
P=Q
60
Q=R
none of the
above.
90
Q=2R
120
none of the
above
ENGINEERING MECHANICS- OBJECTIVE QUESTIONS ( UNIT II)
QUESTIONS
1
A
Which of the following is a scalar quantity ? force
B
C
D
speed
velocity
Acceleration.
If a body is moving with a uniform
2 acceleration ‘a’, then the distance traveled ((u +a)/2) ( 1-2n)
by the body in nth second is given by
((u +a)/2)(n-2)
u + (a/2)(2n-1)
none of above
When two bodies of mass (m and 2m) equal to the
half the
are connected by a light inextensible string acceleration of the two times the
3
acceleration of the acceleration of the none of above
other body
and pass over a smooth pulley, then
other body
other body
acceleration of of one body is
When two bodies of mass (m and 2m) are
connected by a light inextensible string
4
and pass over a smooth pulley, then
tension in both
sides of string will
be equal
The time taken by a ball ( of weight 500gm) to
return back to earth , if it is thrown
5
vertically upward with a velocity 4.9 m/sec ½ sec
is equal to
.
The maximum height attained by a ball(
of weight 500gm) which is thrown
100cm
6
vertically upward with a velocity 4.9 m/sec
is equal to
The maximum height reached by a
stone ( of weight 5Kg) which is thrown
vertically upward with an initial
7
20m
velocity 19.6 m/sec would be
A body is moving with a velocity of 2m/sec . If
the velocity of body becomes 5m/sec
8
after 4 sec., the acceleration of the body
would be
A body is moving with a velocity of
9 10m/sec. The time required, to stop the
body within a distance of 5m, is equal to
10
one Newton is force acting on a mass of
1m/sec2
3 sec
tension in one side
of string is two
times the tension in
the other side of the
string.
tension in one
side of the string
is half the tension none of above
in the other side
of the string
1 sec
2 sec
3 sec
245 cm
122.5 cm
980cm
19.6m
30m
25m
0.75 m/sec2
1.5m/sec2
0.375 m/sec2
5 sec
1sec
0.5 sec
one gm to produce one Kg to produce
one Kg to produce
an acceleration of an
an acceleration of none of above
one m/sec2
acceleration of
one cm/sec2
one m/sec2
velocity x
mass x Change of
velocity
moment x
distance
acceleration
The gravitational accelearation at a place is
one sixth of
6 times the value of gravitational
weight at earth
12
acceleration at earth, the weight of body at
that place will be
same as at earth
6 times the
weight at earth
none of the
above.
13
v(dv/ds)
d2s/dt2
All of the above
11 Momentum of a body is given by
The liner acceleration ‘a ‘ is equal to
mass x velocity
dv/dt
If the body falls freely under gravity, then the
gravitational acceleration is taken
14
as
+8.9m/s2
If the gravitational acceleration at any place is
doubled, then the weight of a body
15
g/2
will be
16
The velocity of a body on reaching the
ground from a height h, is
2√gh
The foce applied on a body of mass 100kg to
20N
produce an acceleration of 5m/s2, is
When the two ships are moving along inclined
directions, then the time when the
Velocity of one of
18
two ship will be closest together depends
the ships
upon
17
– 8.9m/s2
(+) 9.8 m/s2
– 9.8 m/s2
g
√2g
2g
√gh
√2gh
2g √h
100N
500N
none of the
above.
velocity of both the angle between the
all of the above
ships
two directions d
Two masses of 10Kg and 15Kg are connected
to two ends of an inextensible rope and pass
acceleration of the
over a smooth pulley. The 10 Kg mass is lying
tension in the
tension in the string
system will remain above a) & b)
19 over a rough plane, which .
string will increase will decrease
the same
is inclined at an angle of 250 with the
horizontal. If this angle is made 30o, then
rotational
curvilinear
none of the
above
g( m1 m2)/(m1+m2)
g( m1m2)/(m1m2)
g(
m1m2)/(m1+m2
)
70.75m
100m
35.375m
gcos θ
(-)gcosθ
gsinθ
gtanθ
24 Acceleration is equal to
ds/dt
dv/dt
d3s/dt3
d2v/dt2
25 ‘D’Alermbert’ Dynamic equilibrium equation is
F= ma
F-ma = 0
ma + F = 0
F + ma = m
(-)4/9 m/s2
0 m/s2
1 m/s2
20
If a body is moving in a straight line, the motion
of the body is called
Two bodiesof masses m1 and m2 are
connected by alight inextensible string and
pass over a smooth pulley. If the mass
21
m1 is coming down , the the acceleration of
both the bodies is equal to
rectilinear
g( m1 + m2)/(m1m2)
A stone dropped into a well is heard to strike
the water after 4 seconds. If the
22
velocity of sound is 350 m/sec, the depth 150m
of well would be
The acceleration of a body moving down an
inclined smooth plane is equal to ---,
23
where θ = Inclination of plane with
horizontal.
For a particle moving along a straight line,
position x is expressed by x = t3-2t2+5
where
26
x is in m and t is in s. Particle's
acceleration when t =2/3 s is
5/9 m/s2
For a particle moving along a straight line
starting from x = 6m, velocity v is
27 expressed by v = 2t2- 8t where v is in m/s
and t is in s. The minimum velocity
8 m/s
attained by the particle is
0 m/s
(-)8 m/s
none of the abo
For a particle moving along a straight line,
position x is expressed by x = t3-2t2+5
28
where x is in m and t is in s. The velocity
attained by the particle will be zero at
t = 0 and 4/3 s
29 Absolute motion of particle is
t = 0 and 2/3 s
t = 1 and 2 s
none of the above
The motion of
particle with
reference to fixed
axies
The motion of
particle with
reference to axies
The motion of
particle with
reference to
movable axies
none of the above
zero
uniform
30 UNIT-5
When an object is moving with uniform
velocity, what is its acceleration?
Negative acceleration means an object is
32
moving with ________ .
A car starting from rest acquires a velocity
33 of 36 km/h in 5 seconds. Calculate its
acceleration
What is the final velocity of a body
34 moving against gravity when it attains the
maximum height?
A stone is dropped from a cliff. Its speed
35
after it has fallen 100 m is
A feather and a coin released
simultaneously from the same height do
36
not reach the ground at the same time
because of the _______.
A motorist traveling at a speed of 72
kmph sees a traffic signal 200 m ahead of
37 him turn red. Determine the deceleration
so that he will just stop at the signal
31
38
constant speed
3 m/s2
zero m/s2
2 m/s2
none of the above
Zero
u2/2g
h/t
2gh
a)9.8 m/s
b)44.2 m/s
c)19.6 m/s
d) 98 m/s
c) force of
gravitation
d) difference in
mass
-2 m/s2
-1.5 m/s2
-2.5 m/s2
They pass each
other
They are at rest
velocity
speed
They are
starting from
rest
distance
b) 45.530 N of E
48.220 N of W
48.220 N of E
290 N
300 N
390 N
500 N
590.50N
1000 N
1090 N
Tangential to point
Perpendicular to
point
Parallel to point
None of these
a) resistance of the
b) force of gravity
air
-1 m/s2
39 The slope of a v-t graph gives______.
acceleration
At an instant, car A and car B are traveling at
speeds of 75 km/h in north direction and 67
km/h in East direction, respectively. Determine
40
45.530 N of W
the direction of relative velocity of A with
respect to B.
A boy of mass 50 kg stands in a lift. Determine
the force exerted by the boy on the floor of the
200 N
41 lift when the lift moves down with a constant
acceleration of 2 m/ s2
43
In curvilinear motion of particle, velocity vector
at a point on curve is----------
negative
increasing speed decreasing speed uniform speed
What do you infer, if S-t graphs of two cyclists
They collide
meet at a point?
boy of mass 50 kg stands in a lift. Determine
the force exerted by the boy on the floor of
42
the lift when the lift moves up with a
constant acceleration of 2 m/ s2
non-uniform
The rectilinear motion of particle can be
considered as special case of curvilinear
motion,
44
in which radius of curvature of particle is--45
In uniform circular motion, tangential
acceleration component is-----
The position of particle in plane is defined by
two coordinates x and y, these displacements
46
are represented as function of---------
Infinity
Finite
Zero
All of these
Zero
Twice of normal
acceleration
Half of normal
acceleration
None
Velocity
Acceleration
Time
Displacement
The velocity of particle is defined by V=t2, the
particle is moving along a curve of radius
47
4m, normal acceleration component of
particle is -----m/s2 at t=4 sec
48
The time of flight of a Projectile on an up ward
inclined plane depends upon
For a given initial velocity of 9.81 m/s,
maximum range is ------ m
The roller coaster car is traveling at speed of
21 m/s, when they pass over the top of curved
hill. If the radius of curvature is 21 m, the
50
acceleration of car as they pass over the top of
hill is -------m/s2
49
51
5
22
An angle of super elevation on curved surface
Velocity
is independent of -----of vehicle
When roads are banked---- component of
normal reaction partly balances the outward
54
Vertical
centrifugal force
what is acceleartion component along
56 tranverser direction of particle moving along
circular path
21
ar = r..+r theta .2
9.81
53
During a race, the dirt bike was observed to
leap up off the small hill at an angle of 60
degree
with horizontal with a speed of 4m/s, the
55
point of landing is 6m away, time taken by bike
to
land was --- seconds
18
4
angle of
d)None of these
inclination of the both a) and b)
angle of projection
plane
15
20
30
9.81
what is acceleartion component along radial
ar = r..-r theta .2
direction of particle moving along circular path
A motor cycle stuntman drives his motorcycle
in a spherical cage in a vertical circle of radius
9.81m, the minimum velocity with which he
52 should drive his motorcycle, so that he does
not lose contact with cage at top of circular
path is ------ m/s
15
a) 4
58
ar = r.-r theta .2
8.86
100
ar = r..-r theta 2
11
10.81
Acceleration due to Radius of
gravity
curvature
mass
horizontal
Orthogonal
oblique
b)3
c)1
d)9.81
a theta =2r.theta. - a theta
rtheta
=2r.theta.+rtheta..
a theta
a theta =2r.theta. =2r.theta. rtheta..
rtheta.
A car is traveling through dip of road, the
apparent weight of driver is ------ the weight of
57
Less than
driver on level road
The polar coordinates of point p are r and Ѳ at
given instant, performing motion, at that
58
instant, at point p, ------------component of Radial
acceleration exists.
In case of unbanked curved road, safety of
vehicle is increased by -------- height of centre
59 of gravity of loaded vehicle from ground
Increasing
surface
60
The range of projectile is maximum, When the
30 degree
angle of projection is
Equal to
More than
All of these
Transverse
Radial and
Transverse
none
Decreasing
Without changing None of these
45 degree
60 degree
90 degree
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
2.5
bove.
above
above
above
A
A
A
B