unit 4 final.pdf

Gaurav Burhade’s Structure Academy |Contact No.: 8551988111 1
Gaurav Burhade’s
STRUCTURE ACADEMY
1. A pendulum of length 2m is released from rest in horizontal position. The velocity of
bob when string forms an angle of 300 with initial horizontal position is …..
a) 4.43m/s b) 3.15m/s c) 2.89m/s d) 5.67m/s
2. A body of mass 3kg is released from top of a 10m high. The velocity of body when it
strikes the ground is …….
a) 12m/s b) 10m/s c) 14m/s d) 8m/s
3. A trolley of mass 125kg moves on a level track for a distance of 100m. If the
resistance of track is 100N. Workdone in moving the trolley is……..
a) 40kJ b) 10kJ c) 12.5kJ d) 50kJ
4. A spring of constant 20N/mm is stretched by 25mm, the workdone is ………
a) 6.25J b) 5J c) 2.5J d) 10J
5. A horse pulling a cart by applying a constant pull of 300N and walks at 2m/s. The
workdone by the horse in 5min is ……
a) 200kJ b) 180kJ c) 600kJ d) 150kJ
6. The power of engine which can do work of 800 joules in 8 sec, is …….
a) 100 watt b) 200 watt c) 300 watt d) 400 joules
7. a body of mass ‘m’ is projected up a 250 incline with a velocity of 15m/s, if μk =
0.25. The maximum distance the block will move up is …..
a) 15m b) 10m c) 18m d) 20m
8. A 20gm bullet is fired with a velocity of 600m/s into a wooden block of mass 4.5kg
at rest μk = 0.4. The block will move …….
a) 0.9m b) 1.2m c) 1.6m d) 2m
9. A ball of mass m is thrown vertically upwards with a velocity of 20m/s. The ball
goes upto maximum height and then strikes the ground. The potential energy is
…….
a) 2mgh b) zero c) mgh d) mgh/2

10. A 100 N force is applied to a body, moving over horizontal plane, at an angle of 60° with the
horizontal. Find out the impulse due to 100 N force during a time interval of 3 s.
A) 100 Ns B) 150 Ns C) 125 Ns D) 0 Ns
11. Calculate the work done by the gravity action on 70 kg student sliding down 300
inclined
plane who slides a slant distance of 10 m.
A) 3430 J B) 4330 J C) 4444 J D) 3034 J
12. A glass marble drops from a height of 3 meters upon a horizontal floor. If the coefficient of
restitution be 0.9, find the height to which it rises after the impact.
A) 2.00m B) 2.43m C) 3.42m D) 1.00m
13. A ball is dropped from a height of 9 meters upon a horizontal slab. If it rebounds to a height
of 5.76 meters, the coefficient of restitution is:
A) 0.6 B) 0.4 C) 0.8 D) 0.9
14. A ball dropped from a height h1 = 1600 mm is observed to rebound to a height h2 = 1100 mm
from a horizontal floor. Determine the coefficient of restitution.
A) 0.60 B) 0.83 C) 0.93 D) 1.00
15. A 25 N force is applied to a body for 2 s , What is the impulse due to the applied force on to
the body?
A) 25 Ns B) 50 Ns C) 2 Ns D) 0 Ns
16. A body of mass 5 kg is taken from a height 5 m to 10 m, the increase in its potentional
energy is (Take g = 10 m/s2
)
A) 250 Nm B) 75 Nm C) 25 Nm D) 50 Nm
17. A 10 kg body is moving with a constant acceleration of 4 m/s2
. If initial velocity of the body
is 2 m/s, determine the change in momentum in 2 s.
A) 120 Ns B) 80 Ns C) 150 Ns D) 40 Ns
18. The kinetic energy of a body of mass 2 kg moving with a speed of 10 m/s is
A) 20 Nm B) 10 Nm C) 100 Nm D) 40 Nm
19. A man of 60 kg mass runs so that his kinetic energy is 750 Nm . The velocity of man is
A) 25 m/s B) 5 m/s C) 12.5 m/s D) 45000 m/s
20. A 10 kg body is moving with a constant acceleration of 3 m/s2. If initial velocity of the body
A) 30 Ns B) 100 Ns C) 50 Ns D) 0 Ns
21. A body hits the ground with 50 m/s velocity and has inelastic collision with the ground then
with what velocity it will rebound if the coefficient of restitution is 0.2

A) 1/250 m/s B) 250 m/s C) 1/10 m/s D) 10 m/s
22. A 1 kg body is dropped from a height of 5 m above the ground. What is total energy of the
body as it strikes the ground?
A) 0 J B) 2 J C) 5 J D) 49.05 J
23. A 10 kg body is thrown upward with a velocity of 50 m/s. Find the K.E. of the body after 2 s
A) 10 x 30.38 J B) 15 x 30.38 J C) 5 x (30.38)2
J D) 0 J
starting from rest. Determine the
change in momentum in 3 s.
A) 20 Ns B) 40 Ns C) 30 Ns D) 0 Ns
25. A body of weight 50 N is moving down 30° inclined plane. Find the work done by the
weight if the body moves through a distance of 0.3 m.
A) 5 J B) 10 J C) 7.5 J D) 100 J
26. A truck weighing 5 x 103
kg and a cart weighing 50 kg are moving with same speed. The
comparison of kinetic energy of truck with cart.
A) 1:1 B) 1:10 C) 10:1 D) 1:2
27. A 100 N force is applied to a body, moving over horizontal plane, at an angle of 60° with the
horizontal. Find out the impulse due to 100 N force during a time interval of 5 s.
A) 100 Ns B) 250 Ns C) 125 Ns D) 200 Ns
28. 50 gm glass marbles dropped from a height of 10 m rebounds to height of 7 m calculate impulse?
A) 2.185 Ns B) 6.285 Ns C) 8.125 Ns D) None of the Above
starting from rest. Determine
the change in momentum in 4 s.
A) 60 Ns B) 45 Ns C) 30 Ns D) 50 Ns
. If initial velocity of the body
A) 120 Ns B) 100 Ns C) 150 Ns D) 90 Ns
31. A man raises a box of 50 kg mass to a height 2 m in 2 minutes, while another man raises the
same box to the same height in 5 minutes , the ratio of the work done is
A) 1:2 B) 1:1 C) 2:1 D) None of the above
32. An elevator weighing 500 kg is to be lifted up at a constant velocity of 0.20 m/s. What would be the
minimum power of the motor to be used?
A) 1000 W B) 1200 W C) 980 W D) 880 W

33. A man having a mass of 80 kg runs up a flight of stairs in 5 s. Determine the power required by
the man, if the flight of the stair is 3.5 m high.
A) 548 W B) 458 W C) 845 W D) 584 W
34. A 5 kg body is dropped from a height of 50 m, find the K.E. of the body after 2 s
A) 5 x (19.62)2
J
B) 2.5 x (19.62)2
J
C) 2.5 x (9.81)2
J
D) 10 x (9.81)2
J
35. A body of weight 10 N is moving down 30° inclined plane. Find the work done by the weight
if the body moves through a distance of 0.1 m.
A) 0 J B) 0.5 J C) 1 J D) 5 J
36. Rail road car A of mass 15 Mg is traveling at 2 m/s on a horizontal track. Car B of mass 13
Mg is traveling towards A at 0.8 m/s. If the car meet and couple together find the speed of
the coupled cars just after the coupling.
A) 0.5 m/s B) 7.0 m/s C) 0.7m/s D) 70 m/s
37. A body of weight 20 N is moving down 30° inclined plane. Find the work done by the weight
if the body moves through a distance of 0.1 m.
A) 1 J B) 0 J C) 2 J D) 3 J
38. A machine raises a load of 100 N through a height of 8 m in 5 s, the power at which the
machine works is
A) 800 W B) 500 W C) 4000 W D) None of the above
39. A lift is used to carry 8 persons through a height of 30 m in two minutes. If the average mass
of each person is 95 kg, determine the power required.
A) 1375 W B) 2174 W C) 1742 W D) None of the above
40. A 2 kg body is moving with constant acceleration of 4 m/s2
starting from rest. What is work
done by the force acting on the body in 4 s.? (Assume no friction)
A) (80 x 16 ) N-m
B) (20 x 8 ) N-m
C) (8 x 32 ) N-m
D) (40 x 8) N-m
41. A 10 kg body is moving with constant acceleration of 4 m/s2
starting from rest. What is work
done by the force acting on the body in 4 s ? (Assume no friction)
A) (10 x 80 ) N-m

B) (10 x 8 ) N-m
C) (10 x 4 ) N-m
D) (100 x 32 ) N-m
42. A car starts from rest and accelerates to 30 kmph. Later, it gets on a highway and accelerates
to 60 kmph.Which part of journey takes more energy?
A) 0-30 kmph
B) 30-60 kmph
C) Both the same
D) None of the Above
43. A 5.00 kg particle has a velocity of (3.00 i – 4.00j) m /s. Find its x and y components of
momentum.
A) (15.00i – 20.00j)
B) (20.00i -15.00j)
C) (25.00i -10.00j)
D) (20.00i -20.00j)
44. A steel ball of weight 0.01 N falls from a height 6 m and rebounds to a height of 4 m find the
impulse.
A) 0.2300 Ns
B) 0.1962 Ns
C) 0.3200Ns
D) 0.9182 Ns
45. In which of the following case, is work being done?
A) A man pressing a wall
B) A coolie standing with a load of N on his head
C) A boy climbing up a stair case
D) None of the above
46. What is Impulse Momentum Principle?
A) Change in K.E. = Work done
B) Impulse of a force system = Change in momentum
C) Change in Impulsive force = Change in K.E
D) Change in P.E. = Change in Kinetic Energy
47. The impulse-momentum principle is applicable
A) If there is no external force acting on the body
B) When the momentum is conserved
C) Only when body hits another body
D) Whenever Newton’s law is applicable

48. If e = 1, it indicates:
A) The impact is plastic
B) The impact is elastic
C) The impact is neither elastic nor plastic
D) none of the above
49. A 5 kg body is moving down 45° incline from rest for which μK = 0.2. Which of the
following principle is applicable for analysis?
A) Principle of Energy conservation
B) Principle of momentum conservation
C) Work Energy principle
D) Principle of virtual work.
50. What is the range for values of e?
A) 0 to 1
B) 0 to 100
C) 10 to 100
D) 0 to 0.1
51. If mass of moving body is much greater than the mass of the body at rest then the
approximate velocity of the moving body after head on collision is
A) Same and in same direction
B) Same and in apposite direction
C) Different and in same direction
D) Different and in opposite direction
52. The ball of mass 10 gm is dropped on the ground from a height of 10 m. It rebounds to a height of
2.5 m. If the ball is in the contact with ground for 0.01 s, then which statement is correct?
A) Impulse force between the ground and the ball is 15 N
B) Impulse force between the ground and the ball is 5 √2 N
C) Coefficient of restitution between the ground and ball is ¼
D) Coefficient of restitution between the ground and ball is ½
53. A mass of a moving cart is doubled keeping the velocity same, the kinetic energy
A) Remains same
B) Gets doubled
C) Gets Trippled
D) Will become half
54. Central impact of two bodies
A) Can only be direct impact
B) Must always be elastic impact
C) May either be direct or indirect

55. A ball hits the floor and rebounds after an inelastic collision. In this case:
A) The momentum of the ball just after the collision is the same as that just before the
collision.
B) The mechanical energy of the ball remains the same in the collision.
C) The total momentum of the ball and the earth is conserved.
D) The total energy of the ball and the earth is conserved.
56. In case of Elastic impact:
A) Momentum is only conserved
B) Energy is only conserved
C) Neither momentum nor Energy is conserved
D) Both momentum and energy is conserved.
57. What is unit of Impulse?
A) N-m
B) Joule
C) N m/s
D) Ns
58. If a body hits the ground from a height h1 and rebounds to a height h2 after having inelastic
collision with the ground then the coefficient of restitution is
A) e = h2/h1
B) e = h1/h2
C) e =√h2/h1
D) e = √ h1/h2
59. Momentum is defined as the product of ------
A) Mass & time C) Mass & distance
B) Mass & acceleration D) Mass & velocity
60. For a perfectly plastic central impact
A) The entire kinetic energy of the two bodies must be lost
B) The two bodies must move stuck together, whether the impact is direct or indirect
C) The two bodies must move stuck together only if the impact is direct
D) A body initial at rest, should stay at rest
61. To keep the kinetic energy of the body same , if its mass is increased four times, the velocity will
get
A) Doubled B) Trippled C) Halved or half D) Remain Same
62. Which of the following statements is correct?
A) K.E. is by virtue of position
B) P.E. is by virtue of position

C) K.E. can be negative
D) none of above
63. When two bodies collide without the presence of any other forces or force fields,
A) Their total momentum must be conserved
B) Their total kinetic energy must be conserved
C) The collision must be direct
D) The collision must be central
64. A ball tied to a string is being whirled around a circle. What can you say about the work done
by tension?
A) Tension does no work at all
B) Tension does negative work
C) Tension does positive work
65. A box is being pulled up a rough incline plane by a rope connected to a pulley. How many
forces are doing work on the box?
A) One force
B) Two forces
C) Three forces
D) Four forces
66. By what factor does the Kinetic Energy of a car change when its speed is trippled?
A) No change at all
B) Factor of 3
C) Factor of 6
D) Factor of 9
67. A box is being pulled across a rough floor at a constant speed, What can you say about the
work done by friction?
A) Friction does not work at all
B) Friction does negative work
C) Friction does positive work
68. How does the work required to stretch a spring by 20 mm compare with work required to
stretch it by 10 mm?
A) Same amount of the work
B) Twice the work
C) Four time the work
D) Eight time the work
69. One Joule 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 cm
D) A force of 1 dyne displaces a body by 1 m
70. Mike performed 5 J of work in 10 seconds, Joy performed 3 J of work in 5 s, who
produced more power?
A) Mike
B) Joy
C) Both produced the same amount of power
D) Zero power
71. At what point the potential energy of a body is taken to be Zero ?
A) At 1m above earth surface
B) At 5m above earth surface
C) On the earth surface

Gaurav Burhade’s
STRUCTURE ACADEMY
Assignment
A) Work Energy Principle
1. If a body moves horizontally through a distances the work done by gravity is
a) mg
b) mgs
c) zero
d) gs
2. One watt is equal to
a) 0.1 J/s
b) 1 J/s
c) 10 J/s
d) 100 J/s
3. A 20 gm bullet is fired with a velocity of 600m/s into a wooden block of mass 4.5 kg
at rest µk=0.4 . The block will move
4. A body of mass 5 kg is thrown down with a velocity of 20 m/s. The K.E. at t= 2 sec
is
5. Find the average resistance required to stop a car of mass 500 kg in a distance of 25
m, if the initial speed is 20 m/s
6. A block of mass 2 kg rest on an incline plane of 300
. The block is pulled by 20 N
force acts for 2 sec. The work done by applied force is
7. Work-energy principle relates
a) Force, acceleration and time
b) Force, velocity and displacement
c) Force, velocity and time
d) Force, displacement and time

8. When a body lifts up , the work done by gravity is
a) Positive
b) Negative
c) Zero
d) None of these
9. A gun of mass 20 kg fires a bullet of mass 25 gm with a velocity of 200 m/s. The
recoil velocity of gun is
10. A projectile is fired with kinetic energy E so that is covers maximum range. The
K.E. at top of trajectory is
a) E
b) E/2
c) E/4
d) Zero
11. The slope of graph of K.E. v/s distance is proportional to
a) Velocity
b) Acceleration
c) Distance
d) Time
12. A motorist travelling at a speed of 72 kmph suddenly applies brakes and comes to a
stop after skidding 40 m. If g=10 m/s2
value of µk is
13. The total work done on a particle is equal to change in K.E.
a) Always
b) Only when force are conservative
c) Only when no external force acting
d) None of these
14. The work done by a conservative force over a closed loop is always
a) Positive
b) Negative
c) Zero
d) None of these
15. One metric horsepower is equal to
a) 1kw
b) 1W

c) 736W
d) 746W
16. If K.E. of a projectile at top of trajectory is one fourth of its K.E. at the start , the
angle of projection will be
17. A 120 gm mass has a velocity v=2i+5j m/s at a certain instant , KE of the body at that
instant is
18. A particle of mass 0.5 kg travels in a straight line with velocity v=5x3/2
, the work
done by the net force during its displacement from x=0 to x=2 m is
19. A uniform force of 4 N acts on a body of mass 40 kg for a distance of 2 m. The KE
acquired by the body is :
20. A spring is kept compressed by a small cart of mass 150 gm. On releasing the cart, it
moves with a speed of 0.2 m/s. The PE of the spring is
21. A body moves a distance of 5 m along a straight line under the action of a force of 10
N. If the work done is 25 J , then the angle which the force makes with the direction
of motion of the body is
22. The displacement x of a particle of mass m kg moving along a straight line is given
by t=√x+3, the work done in first 6 sec is
23. A spring of constant 800 N/m has an extension of 5 cm. The work done in extending
it from 5 cm to 15 cm is:
24. The kinetic energy K of a particle moving in straight line depends upon the distance s
as : K=aS2
the force acting on the particle is
a) 2 a s
b) 2 m a s
c) 2 a
d) √as2
25. When a man increases his speed by 2 m/s , he finds that his kinetic energy is doubled
, the original speed of the man is

B) Impulse –Momentum Theorem and Impact
1. Two particle of masses m1 and m2 have same momentum the ratio for their kinetic
energy is
2. Impulse momentum principle is derived from
a) Newton’s 1st
law
b) Newton’s 2nd
law
c) Newton’s 3rd
law
d) Newton’s gravitational law
3. If the external impressed force on the system is zero the total momentum of
system is
a) Increased
b) Decreased
c) Remain constant
d) None of these
4. The speed of a body changes from v to 2v. The momentum changes its magnitude
from p to p.
a) 1/4
b) 1
c) 2
d) 1/2
5. Two masses of 1 kg and 4 kg are moving with equal K.E. The ratio of the
magnitude of linear momentum
6. The unit and dimension of the following quantity are the same as those of impulse
a) K.E.
b) Moment of force
c) Momentum
d) Acceleration
7. Both bodies move together after impact when impact is
a) Elastic
b) Semi elastic
c) Both a) and b)
d) None of these
8. When coefficient of resolution is zero impact is
a) Plastic
b) Elastic
c) Semi elastic
d) Both a) and b
9. In an inelastic impact
a) Initial K.E.= Final K.E.
b) Initial K.E.< Final K.E.
c) Initial K.E.> Final K.E.

d) K.E. remains constant
10. The common normal to the plane of contact during impact is
a) Line of impact
b) Line of compact
c) Central line
d) Direct line
11. The loss of KE in elastic impact is zero
a) True
b) False
c) Can not predict
d) None
12. A body of mass m is moving with constant velocity ‘v’ hits another body of
same mass at rest for plastic impact the common velocity is
a) Zero
b) v/2
c) v
d) 2v
13. The bodies which rebound after impact are called
a) Inelastic bodies
b) Elastic bodies
c) Neither Elastic nor inelastic bodies
d) None of these
14. A ball is dropped from a height of 12 m on the floor. If e=0.89, the bouncing
height will be
15. For perfectly elastic impact
a) e=0
b) e=1
c) e=-1
d) e→∞

unit 4 final.pdf

Empfohlen

Empfohlen

Weitere ähnliche Inhalte

Ähnlich wie unit 4 final.pdf

Ähnlich wie unit 4 final.pdf (10)

Mehr von Mansi Kakani

Mehr von Mansi Kakani (7)

Kürzlich hochgeladen

Kürzlich hochgeladen (20)

unit 4 final.pdf