PHYSICS CHAPTER 2 Vectors and Equilibrium
1.
Which
one of the followings is a scalar?
(a)
Energy (b)
Velocity
(c) Force (d)
Torque
2. Which one of the followings is a vector?
(a)
Length (b)
Volume
(c) Velocity (d)
Work
3. In which one of the followings are all the
three quantities vectors?
(a)
Displacement,
velocity, energy
(b)
Force,
work, energy
(c)
Displacement,
velocity, momentum
(d)
Velocity,
acceleration, power
4. The reverse process of adding two vectors is
called
(a)
multiplication
(b)
subtraction
(c) resolution (d) none of these
5. The resultant of two vectors of equal
magnitude inclined at some angle is equal to the magnitude of either of the two
vectors. The angle between the two is
(a)
60° (b)90°
(c) 120°
(d)
180°
8. The result of adding A into – A is
(a)
A (b)
2 A
(c)
O (d) 0
9. The unit vector of a vector A is given by
^ ^ A
(a)
A = A A (b)
A =
A
^ A ^ A
(c) A
= (d)
A =
A A
10. When a certain vector is multiplied by – 1,
then the direction of the vector changes through
(a)
90° (b)
120°
(c) 150° (d)
180°
11. Rectangular components make an angle of
(a)
0° (b)
60°
(c) 90°
(d)
120°
12. The minimum number of unequal forces whose
vector sum is zero must be
(a)
1 (b)
2
(c) 3
(d)
4
13. One of the rectangular components of a
velocity of
50 ms-1 is 30 ms-1. The
other component in ms-1 is
(a)
15 (b)
20
(c)
25 (d)
40
^ ^
14. For the two vectors Ax = (20 N) i , Ay= (20 N) j , the angle made by
the resultant vector A with the x-axis is
(a)
45° (b)
135°
(c) 215°
(d)
315°
15. Which of the following forces cannot be
added to give of a resultant of 2 N?
(a)
1
N and 1 N (b) 1 N and 2 N
(c) 2
N and 2 N (d)
1 N and 3 N
17. Two forces act together on an object. The
magnitude of their resultant is least when the angle between them is
(a)
45° (b)
60°
(c) 90°
(d)
180°
18. If |A+B| = |A – B| where A and B are two
vectors of equal magnitudes, then the angle between A and B is
(a)
0° (b)
60°
(c) 90°
(d)
180°
^ ^
19. The angle subtended by r = 3 i + 4 j
with x-axis is
(a)
53° (b)
30°
(c) 41° (d)
60°
^ ^
20. The magnitude of a vector A = Ax i –
Ay j is
(a)
A2x + A2y (b)
Ax2 + A2y
(c)
A2x – A2y (d)
A2x – A2y
21. The dot product of two non-zero vectors
equals the product of their magnitudes only if the angle between them is
(a)
0° (b)
90° (c) 120°
(d)
180°
22. For which of the followings pair of angles,
the dot product of two vectors is equal to the one half of the product of magnitudes of two vectors?
(a)
60°
and 120° (b) 60° and 240°
(c)
60° and 300° (d)
none of these
23. For a vector A,
(a)
A
• A = 0 (b) A • A
= 1
(c) A • A = A (d) A • A
= A2
24. Which one of the followings is correct?
^ ^ ^ ^ ^
(a)
i •
j = k (b) i
• j = 0
^ ^ ^ ^ ^
(c) i
• j =
1 (d) i
• j = –k
^ ^ ^
25. Given A = 2i – 2j + k , the magnitude of this vector is
(a)
1 (b)
2
(c) 3
(d)
5
26. If A B lies along + z-axis, the vectors A and B will be in
(a)
xz-plane (b)
xy-plane
(c) yz-plane (d)
x-direction only
27. The cross product of two non-zero parallel
vectors A and B is
(a)
AB
sin (b)
AB
^
(c) AB sin
n (d) O
28. Which of the followings is incorrect?
^ ^ ^ ^ ^ ^
(a)
i
j = k (b) k
j = –
i
^ ^ ^ ^
(c) j
j
= 0 (d) i
j =
0
^ ^ ^ ^
29. If A = Ax i + Ay j and B = Bx i + By j are two non-
parallel vectors, then
the direction of A B is along
(a)
A (b) B
(c) x-axis (d)
z-axis
^ ^ ^ ^
30. If A = A1 i + A2 j and B = B1 i + B2 j , the
number of components in the vector A
B
is
(a)
1
only (b)
2 only
(c) 3 only (d)
4 only
31. If A B = 0 and A
B = 0, then
(a)
either
A or B is a null vector.
(b)
A
and B are non-parallel.
(c)
A
and B are perpendicular to each other.
(d)
A
and B are parallel to each other.
32. The vector product is
(a)
commutative (b)
anticommutative
(c)
associative (d)
additive
33. The cross product of two vectors has a
magnitude equal to the product of their magnitudes. Their dot product is equal
to
(a)
AB
sin (b)
AB cos
(c) AB (d)
0
34. Torque produced by a force depends upon
(a)
magnitude
of the force and the angular velocity
(b)
magnitude
of the force and displacement (c)
magnitude of the force and moment arm
(d)
force and acceleration of the body.
35. A couple consists of
(a)
two
equal and opposite forces acting at two different points on the body
(b)
two
equal and parallel forces acting at two different points (c) two equal and opposite force acting at a
point on the body (d) two
equal and parallel force acting at a point on the body.
36. The arm of a couple is
(a)
any
distance between the forces
(b)
the
shortest distance between the forces
(c)
perpendicular
distance between the two forces (d)
the longest distance between the two forces.
37. If the resultant of all the forces acting on
a body is zero, then the body
(a)
has
angular momentum (b) has acceleration
(c)
is at rest (d) is in translational equilibrium
38. Three coplanar forces acting on a body keep
it in equilibrium. The forces must be
(a)
collinear (b)
concurrent
(c) non-concurrent (d) parallel
39. If the line of action of the force passes
through the axis of rotation, then the torque is
(a)
zero
(b) maximum
(c) clockwise in direction (d) counter clockwise in direction
40. ˆi (ˆj k)ˆ equals
(a)
ˆi
(b)
kˆ
(c) 1
(d) 0
Key to Test Chapter 2
1
|
a
|
21
|
a
|
2
|
c
|
22
|
c
|
3
|
c
|
23
|
d
|
4
|
c
|
24
|
b
|
5
|
c
|
25
|
c
|
6
|
d
|
26
|
b
|
7
|
b
|
27
|
d
|
8
|
c
|
28
|
d
|
9
|
c
|
29
|
d
|
10
|
d
|
30
|
a
|
11
|
c
|
31
|
a
|
12
|
c
|
32
|
b
|
13
|
d
|
33
|
d
|
14
|
a
|
34
|
c
|
15
|
b
|
35
|
a
|
16
|
a
|
36
|
c
|
17
|
d
|
37
|
d
|
18
|
c
|
38
|
b
|
19
|
a
|
39
|
a
|
20
|
b
|
40
|
d
|
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