1.
Work means-
(a) effort
(b) interview
(c) achievement
(d) get-together
ANS: achievement
2.
Work is done on a body when-
(a) force acts on the body but
the body is not displaced
(b) force does not act on the body
but it is displaced
(c) force acts on the body in a
direction perpendicular to the direction of the displacement of the body
(d) force acts on the body and
body is either displaced in the direction of force or opposite to the direction
of force
ANS: force acts on the body and body
is either displaced in the direction of force or opposite to the direction of
force
3. When a horse pulls a cart,
who does the work?
(a) cart
(b) wheels
(c) road
(d) horse
ANS: horse
4.
Work done is measured by-
(a) dot product of mass & velocity
(b) dot product of mass &
acceleration
(c) dot product of force &
displacement
(d) dot product of force &
time
ANS: dot product of force & displacement
5. A body is
acted upon by a force which is proportional to the distance covered. If
distance covered be denoted by S, then work done by the force will be
proportional to-
(a) S
(b) S2
(c) S3/2
(d) S2/3
ANS: S2
6. A body is
acted upon by a force which is inversely proportional to the distance covered
(S). The work done will be proportional to-
(a) S
(b) S2
(c) S3/2
(d) None of these
ANS: None of these
7. The work done on an object
does not depend upon the-
(a) displacement
(b) force applied
(c) angle between force and
displacement
(d) initial velocity of the
object
ANS: initial velocity of the object
8.
Work done upon a body is-
(a) a vector quantity
(b) a scalar quantity
(c) both (a) and (b)
(d) none of these
ANS: a scalar quantity
9. Force F acts on a body such
that force F makes an angle θ with the horizontal direction and the body is
also displaced through a distance S in the horizontal direction, then the work
done by the force is-
(a) FS
(b) FS cos θ
(c) FS sin θ
(d) Zero
ANS: FS cos θ
10.
If force and displacement of the particle (in direction of force) are
doubled. Work should be-
(a) doubled
(b) 4 times
(c) halved
(d) ¼ times
ANS: 4 times
11. Work done-
(a) is always positive
(b) is always negative
(c) can be positive, negative or
zero
(d) none of these
ANS: can be positive, negative or
zero
12.
If the force applied on a body displaces it in the same direction, then
work done on the body by the applied force is-
(a) negative
(b) positive
(c) zero
(d) can be positive or negative
ANS: positive
13. When a force accelerates
the motion of a body, the work done is-
(a) positive
(b) negative
(c) zero
(d) undefined
ANS: positive
14.
If the force applied on a body displaces it in the opposite direction,
then work done on the body by the applied force is-
(a) negative
(b) positive
(c) zero
(d) can be positive or negative
ANS: negative
15.
Work done by friction-
(a) accelerates the motion of a
body
(b) retards the motion of a body
(c) has no impact on the motion
of a body
(d) sometimes accelerates and
sometimes retards the motion of the body
ANS: retards the motion of a body
16. When a force retards the
motion of a body, the work done is-
(a) positive
(b) negative
(c) zero
(d) undefined
ANS: negative
17.
In tug of war, work done by winning team is-
(a) zero
(b) positive
(c) negative
(d) none of these
ANS: positive
18.
In tug of war, work done by losing team is-
(a) zero
(b) positive
(c) negative
(d) none of these
ANS: negative
19.
Work done by the force of gravity, when a body is lifted to height H
above the ground is-
(a) zero
(b) positive
(c) negative
(d) none of these
ANS: negative
20. In case
of negative work the angle between the force and displacement is-
(a) 00
(b) 600
(c) 900
(d) 1800
ANS: 1800
21. If the
angle between force and displacement is θ, then for what value of θ, the work done is maximum?
(a) 00
(b) 600
(c) 900
(d) 1800
ANS: 00
22. A rocket
rises upwards in the air due to the force generated by the fuel. The work done
by the-
(a) fuel is negative and that by force of
gravity is positive
(b) fuel is positive and that by force of gravity
is negative
(c) both fuel and force of gravity do positive
work
(d) both fuel and force of gravity do negative
work
ANS: fuel is positive and that by force of gravity
is negative
23. A child
on a skateboard is moving at a speed of 2 m/s. After a force acts on the child,
her speed is 3 m/s. What can you say about the work done by the external force
on the child?
(a) positive work was done
(b) negative work was done
(c) zero work was done
(d) infinite work was done
ANS: positive work was done
24. Rohan
applied 10 N force over 3 m in 10 seconds. Soham applied the same force over
the same distance in 1 minute. Who did more work?
(a) both did the same work
(b) both did zero work
(c) Rohan
(d) Soham
ANS: both did the same work
25. Work
done by tension in the string when a ball tied to a string is being whirled
around in a circle is-
(a) negative work
(b) positive work
(c) zero work
(d) tension does no work at all
ANS: tension does no work at all
26. No work is done when-
(a) a nail is plugged into a
wooden board
(b) a box is pushed along a
horizontal floor
(c) there is no component of
force parallel to the direction of motion
(d) there is no component of
force normal to the direction of motion
ANS: there is no component of force
parallel to the direction of motion
27. A man carrying a bucket of
water and walking on a rough level road with a uniform velocity does no work
while carrying the bucket. Which of the following statements gives the correct
reason for this?
(a) The displacement of the
bucket is zero
(b) There is no force acting on
the bucket
(c) The displacement of the
bucket is in the direction of force applied
(d) There is no displacement in
the direction of the force applied
ANS: there is no displacement in the
direction of the force applied
28. If the angle between force and displacement is θ,
then for what value
of θ is work done zero?
(a) 600
(b) 450
(c) 1800
(d) 900
29. The work done is zero if-
(a) the body shows displacement
in the direction of the applied force
(b) the body shows displacement in
the opposite direction of the applied force
(c) the body shows displacement
in perpendicular direction to the applied force
(d) the body shows displacement obliquely
to direction of the applied force
ANS: the body shows displacement in perpendicular
direction to the applied force
30.
A coolie is carrying a heavy luggage from one platform to the other of a
Railway station but still according to the logics of science, he has done zero
work. Which of the following gives the correct reason?
(a) the force acting along the
direction of displacement of luggage
(b) the force is acting perpendicular
to the direction of displacement of luggage
(c) the force is acting opposite
to the direction of displacement of luggage
(d) none of these
ANS: the force is acting perpendicular to the direction of displacement of luggage
31. A coolie lifts a suitcase and walks from the platform to an overhead bridge. The work done by the coolie is-
(a) zero
(b) positive
(c) negative
(d) incomplete information
ANS: positive
32. When the force applied and the displacement produced in the body are inclined at 900 with each other, then the work done is-
(a) maximum
(b) minimum
(c) zero
(d) infinite
ANS: zero
33. A centripetal force acts -
(a) radially inwards
(b) radially outwards
(c) tangentially
(d) axially
ANS: radially inwards
34.
When a body is revolving around another body in a circular orbit, then
the work done is zero because-
(a) centripetal force acts in
the direction of motion of the revolving object
(b) centripetal force acts along the
radius of the circular path and is perpendicular to the direction of motion of
the revolving object
(c) centrifugal force acts in
the direction of motion of the revolving object
(d) centrifugal force acts along
the radius of the circular path and is perpendicular to the direction of motion
of the revolving object
ANS: centripetal force acts along the
radius of the circular path and is perpendicular to the direction of motion of
the revolving object
35.
Work done by centripetal force is-
(a) zero
(b) > zero
(c) < zero
(d) = 1
ANS: zero
36. The work done by the
gravitational force of Earth on a satellite along a circular path is-
(a) positive
(b) negative
(c) zero
(d) cannot be determined
ANS: Zero
37.
A load is carried through a distance of 5 m in the following different
ways. In which case the work done is maximum?
(a) pushed over an inclined
plane
(b) lifted vertically upward
(c) pushed over smooth rollers
(d) pushed over a wedge
ANS: Lifted vertically upward
38.
A load is carried through a distance of 5 m in the following different
ways. In which case the work done is minimum?
(a) pushed over an inclined
plane
(b) liften vertically upward
(c) pushed over smooth rollers
(d) pushed over a wedge
ANS: pushed over smooth rollers
39. On a
rough surface a mass is (i) pulled, (ii) pushed by a force acting at angle with
the surface.
(a) Pulling is easier
(b) pushing is easier
(c) pushing and pulling both are easier
(d) pushing and pulling are not easier
40.
If a graph is plotted between force and displacement, then the area under
the graph will give us the-
(a) power
(b) momentum
(c) velocity
(d) work done
ANS: work done
41. In a
Force-displacement graph, work done by a body is given by-
(a) area under the curve
(b) slope of the curve
(c) line parallel to the displacement axis
(d) line parallel to the force axis
ANS: area under the curve
42.
Newton-metre is the unit of-
(a) power
(b) work
(c) momentum
(d) gravitational intensity
ANS: work
43. kg.m2.s-2
is associated with-
(a) work done
(b) force
(c) momentum
(d) impulse
ANS: work done
44.
Joule is the unit of-
(a) power
(b) work
(c) momentum
(d) force
ANS: work
45.
1 joule of work is said to be done when-
(a) a force of 1 N displaces a
body by 1 cm
(b) a force of 1 N displaces a body
by 1 m
(c) a force of 1 dyne displaces
a body by 1 m
(d) a force of 1 dyne displaces
a body by 1 cm
ANS: a force of 1 N displaces a body
by 1 m
46.
The CGS unit of work done is-
(a) newton-metre
(b) joule
(c) erg
(d) dyne
ANS: erg
47.
1 erg of work is said to be done when-
(a) a force of 1 N displaces a
body by 1 cm
(b) a force of 1 N displaces a body
by 1 m
(c) a force of 1 dyne displaces
a body by 1 m
(d) a force of 1 dyne displaces
a body by 1 cm
ANS: a force of 1 dyne displaces a
body by 1 cm
48. Choose the correct relation-
(a) 1 J = 105 erg
(b) 1 J = 107 erg
(c) 1 J = 103 erg
(d) None of these
49. Which of the following statements is/are true about work done?
(i) Work done by a force is always positive
(ii) SI unit of work is joule
(iii) Work has both magnitude and direction
(iv) work is said to be done if an object is displaced when a force acts
on it
(a) (i) and (ii)
(b) (ii) and (iii)
(c) (ii) and (iv)
(d) (i), (ii), (iii) and (iv)
ANS: (ii) and (iv)
50. Identify the correct statement about
work.
(a) Unit of work is Newton-metre
(b) The SI unit of work is Joule
(c) Work done is a scalar quantity
(d) All of these
51.
A pair of bullocks exert a force of 1500 N on a plough. The field being
ploughed is 20 m long. The work done in ploughing the given length of the field
will be-
(a) 21000 J
(b) 30000 J
(c) 45000 J
(d) 3000 J
ANS: 30000 J
52.
If 10 N of force is applied to an object, but the object does not move,
then how much work being done by the force?
(a) Zero
(b) 10 J
(c) 10 N
(d) 20 J
ANS: Zero
53.
A body is under the action of the equal and opposite forces, each of 5
N. The body is displaced by 2 m. The work done is-
(a) + 10 J
(b) – 10 J
(c) Zero
(d) 25 J
ANS: zero (because here the net force
acting on the body is zero)
54. A girl is carrying a school bag of 2 kg mass on her back and moves 300 m on a levelled road. The work done against the gravitational force is (g=10 m/s-2)
(a) 6 x 103 J
(b) -6 x 103 J
(c) 6 x 10-3 J
(d) zero
ANS: zero (as the direction of displacement and
force of gravity are perpendicular)
55. A person pulls a body on a horizontal
surface by applying a force of 5.0 N. Find the work done by this force in
displacing the body through 2.0 m.
(a) 10 J
(b) 15 J
(c) Zero
(d) 5 J
ANS: 10 J
56. Work
done in moving a 50 kg block through a distance of 10 m by applying a force of
100 N which makes an angle of 600 with the horizontal is-
(a) 300 Joule
(b) 400 Joule
(c) 500 Joule
(d) 1000 Joule
ANS: 500 Joule
(W = FS Cos 600= ½ x100x10 = 500 J)
57. The work
done by a weight of 1 kg mass when it moves up through 1 m is-
(a) 10 J
(b) -10 J
(c) 0.1 J
(d) -0.1 J
ANS: -10 J
58. A coolie lifts a luggage of 10 kg from
the ground and put it on his head 1.8 m above the ground. The work done by him
on the luggage is-
(a) 180 J
(b) 220 J
(c) 100 J
(d) 480 J
ANS: 180 J
59. A
student carries a bag weighing 5 kg from the ground floor to his class on the
first floor that is 2 m high. The work done by the boy is-
(a) 1 J
(b) 10 J
(c) 100 J
(d) 1000 J
ANS: 100 J
60. A ball of mass 1 kg thrown upwards
reaches a maximum height of 5.0 m. Calculate the work done by the force of
gravity during this vertical displacement.
(a) -49 J
(b) 49 J
(c) 5.0 N
(d) -5.0 N
61.
In which of the following cases the work done is maximum?
ANS: (iii)
62. Four forces of equal
magnitude are acting on an object as shown in figure. Which of the following
forces does the least work?
(a) P
(b) Q
(c) R
(d) S
ANS: Q
63. A body starts from rest and acquires a velocity v in time T. The work done on the body in time t will be proportional to-
(a) vt /T
(b) v2t /T
(c) v2t /T2
(d) v2t2 /T2