11th Physics, Chapter- 5, ( Newtons Laws of Motion)
1. The momentum of a system is conserved
(A) Always
(B) Never
(C) In the absence of an external force on the system
(D) None of the above
Answer
2. On what conservation principle the rocket’s motion is based?
(A) Mass
(B) Kinetic Energy
(C) Linear Momentum
(D) Angular Momentum
Answer
3. A body with constant momentum must have constant-
(A) Force
(B) Acceleration
(C) Velocity
(D) All of these
Answer
4. Recoil speed of a gun is:
(A) Directly proportional to the mass of the gun
(B) Inversely proportional to the mass of gun
(C) Independent of mass of gun
(D) None of these
Answer
5. Why we experiences recoil in a gun after firing a bullet ?
(A) Because the bullet has small linear momentum
(B) Because the bullet has large linear momentum
(C) The bullet has zero linear momentum
(D) None of the above
Answer
6. What is the linear momentum of the gun and bullet before firing:
(A) Large
(C) Zero
(B) Small
(D) Maximum
Answer
7. When a person jumps out of a boat, he push the boat in the:
(A) Forward direction
(B) Downward direction
(C) Backward direction
(D) Upward direction
Answer
8. A bullet of mass 5 gm is fired from a gun of mass 5 kg. What is the velocity of the muzzle if the recoil velocity is 500 m/s.
(A) 500 m/s
(C) 50 m/s
(B) 5 m/s
(D) 0.5 m/s
Answer
9. A rope of length 5 m is kept on a frictionless surface and a force of 5 N is applied to one of its ends. What is the tension in the rope at 1 m from this end?
(A) IN
(B) 3 N
(C) 4 N
(D) 5 N
Answer
10. A wagon weighing 1000 kg moves 50 km/h on smooth rails. Later, a mass of 250 kg is placed in the wagon. What is the velocity with which it moves?
(A) 20 km/hr
(B) 40 km/hr
(C) 50 km/hr
(D) 2.5 km/hr
Answer
11. A particle of mass m collides with a stationary particle of mass 2m and adheres to it at a velocity of v. The system’s speed will be
(A) v/2
(B) v/3
(C) 2v
(D) 3v
Answer
12. A player catches a 150-gram ball travelling at 20 metres per A playerIf the catching procedure needs to be done in second. What is the force that the ball exerts on the player’s hands?
(A) 3000 N
(B) 300 N
(C) 30 N
(D) 0.3 N
Answer
13. Two bodies moving with constant velocities collide with each other. Which of the following quantities remain conserved?
(A) Momentum
(B) Speed
(C) Force
(D) Velocity
Answer
14. A ball is moving with a constant velocity. After some time, it collides with a wall. Which one of the following remains conserved except momentum?
(A) Energy
(B) Displacement
(C) Power
(D) Force
Answer
15. Two bodies of masses 2 Kg and 7 Kg are moving with velocities of 2 m/s and 7 m/s respectively. What is the total momentum of the system in Kg-m/s?
(A) 50
(B) 53
(C) 28
(D) 0
Answer
16. A variable mass body with an initial mass of 10 kg is moving with a velocity of 7 m/s initially, after some time the velocity increases to 14 m/s, what is the new mass if the body is moving in the absence of any external force?
(A) 2.5 Kg
(B) 5 Kg
(C) 7.5 Kg
(D) 10 Kg
Answer
17. If the KE of a body becomes four times of its initial valuc, then the new momentum will be more than its initial ( momentum by;
(A) 50%
(B) 100%
(C) 125%
(D) 150%
Answer
18. A bullet in motion hits and gets embedded in a solid block resting on a frictionless table. What is conserved?
(A) Momentum and KE
(B) Kinetic energy alone
(C) Neither KE nor momentum
(D) Momentum alone
Answer
19. A bomb travelling in a parabolic path under the effect of gravity, explodes in mid air. The centre of mass of fragments will:
(A) Move vertically downwards
(B) Move vertically upwards and then downwards
(C) Move in irregular path
(D) Move in the parabolic path the unexploded bomb would have travelled
Answer
20. A bullet weighing 10 gm and moving at 300 m/s strikes a 5 kg ice and drops dead. The ice block is sitting on a frictionless level sùrface. The speed of the block after the collision, is
(A) 6 cm/sec
(B) 60 cm/sec
(C) 6 m/sec
(D) 60 m/sec.
Answer
21. A massive ball moving with speed v collides with a tiny ball having a mass very much smaller than the mass of the first ball. If the collision is elastic, then immediately after the impact, the second ball will move with a speed approximately equal to:
(A) v
(B) v/2
(C) 2v
(D) 08
Answer
22. A surface is hit elastically and normally by n balls per unit time, all the balls having the same mass m and moving with the same velocity u. The force on the surface is:
(A) mnu²
(B) (1/2)mnu2
(C) 2mnu
(D) 2mnu2
Answer
23. Which of the following is known as law of inertia?
(A) Newton’s first law of motion
(B) Newton’s second law of motion
(C) Newton’s third law of motion
(D) Law of conservation of mass
Answer
24. To shake off water from wet cloth, it is common to give it a sudden jerk. In doing so, we are taking advantage of:
(A) Newton’s first law of motion
(B) Newton’s second law of motion
(C) Newton’s third law of motion
(D) None of these
Answer
25. Action and reaction:
(A) Act on the same body
(B) are equal act in the same direction
(C) Cancel each other
(D) Act on two different bodies
Answer
26. When train suddenly stops, the passengers fall forward it is due to:
(A) Inertia of motion
(B) Inertia of direction
(C) Gravitational pull by earth
(D) None of these
Answer
27. Conservation of momentum in a collision between particles can be understood from:
(A) Conservation of energy
(B) Newton’s first law only
(C) Newton’s second law only
(D) Both Newton’s second and third law
Answer
28. A constant force acts on a body of mass 0.9 kg at rest for 10 s. If the body moves a distance of 250 m, the magnitude of the force is
(A) 3 N
(B) 4 N
(C) 4.5 N
(D) 5.6 N
Answer
29. Newton’s first law of motion is also known as:
(A) Gravity
(B) The law of inertia
(C) Vertical motion
(D) The law of conservation of momentum
Answer
30. Action and reaction are equal and opposite. If f be the magnitude of both the action and reaction, then
(A) Resultant of action and reaction is zero
(B) Resultant of action and reaction = 2f
(C) Resultant of action and reaction is less then f
(D) Action and reaction do not cancel each other
Answer
31. Let Fe, Fg and En represent the magnitudes of electro- magnetic, gravitational and nuclear forces between the two electrons at a given separation, then
(A) Fn > Fe > Fg
(B) Fg > Fn > Fe
(C) Fe > Fn >Fg
(D) Fe > Fg > Fn
Answer
32. Suppose the earth suddenly stops attracting objects place near the surface. A person standing on the surface of the earth will (Neglect the effect of rotation of earth)
(A) Fly up
(B) Slip along the surface
(C) Fly along a tangent to the earth’s surface
(D) Remain standing
Answer
33. Impulse is the product of
(A) Force and time
(B) Momentum and time
(C) Force and acceleration
(D) Momentum and force
Answer
34. A constant retarding force of 50N is applied to a body of mass 10 kg moving initially with the speed of 10ms. The body comes to rest after:
(A) 8 second
(B) 6 second
(C) 4 second
(D) 2 second
Answer
35. S.I. unit of inertia is
(A) unitless
(B) kgm-1
(C) kgm²
(D) kgm-2
Answer
36. Whenever two bodies interact with each other, they exert:
(A) Equal & opposite force
(B) Unequal & opposite force
(C) Equal force but same direction
(D) All of these
Answer
37. Rahul was sitting on the back of a horse. The horse suddenly started running Rahul:
(A) Fell in forward direction
(B) Fell in backward direction
(C) Remained in the sitting position
(D) None of these
Answer
38. If external force on a body is zero, its:
(A) Displacement is zero
(B) Velocity is zero
(C) Acceleration is zero
(D) None of these
Answer
39. The working of a rocket is based on the principle of:
(A) Elasticity
(B) Helper’s Law
(C) Newton’s law of gravitation
(D) Conservation of momentum
Answer
40. The physical quantity which is equal to the change in momentum of a body is know as:
(A) Force
(B) Impulse
(C) Acceleration
(D) Reaction
Answer
41. A car accelerates on a horizontal road due to the force exerted by the:
(A) Road
(B) Driver of the car
(C) Earth
(D) Engine of the car
Answer
42. A ball is travelling with uniform translatory motion means that:
(A) It is at rest
(B) Path can be straight and ball travels with uniform speed
(C) All part of the ball has the same velocity
(D) Centre of the ball moves with constant velocity
Answer
43. The relation F = ma is not valid if:
(A) Force depends on time
(B) Mass depends on time
(C) Acceleration depends on time
(D) Momentum depends on time
Answer
44. The motion of particle of mass m is given by y = ut + gt The force acting on the particle is:
(A) mg
(B) 2mg
(B) mut
(D) 2mu t
Answer
45. When train suddenly starts moving, the passengers fall backward. It is due to:
(A) Inertia of motion
(B) Inertia of direction
(C) Inertia of rest
(D) None of these
Answer
46. Change in momentum is given by the product of:
(A) Force & mass
(B) Force & velocity
(C) Force & time
(D) Force & distance
Answer
47. A body of mass 50g is moving with a constant velocity of 5 ms on a horizontal smooth surface. The force acting on the body is:
(A) IN
(B) 5N
(C) 2N
(D) Zero
Answer
48. Which law is the real law of motion?
(A) First law of motion
(B) Third law of motion
(C) Second law of motion
(D) All of the above
Answer
49. Normal reaction and force of friction are:
(A) Perpendicular to each other
(B) Parallel to each other
(C) Inclined at some angle
(D) All of the above
Answer
50. Force of friction is:
(A) Non-conservative force
(B) Conservative force
(C) Both (A) and (B)
(D) None of these
Answer
51. The force of friction acts in a. of motion of object: to the direction
(A) Same
(B) Opposite
(C) Downwards
(D) Perpendicular
Answer
52. A force of friction depends upon :
(A) Nature of surface of contact
(B) Material of object in contact
(C) Both (A) and (B)
(D) None of the above
Answer
53. At high speed friction is :
(A) Increase
(B) Become zero
(C) Decrease
(D) becomes infinite
Answer
54. Friction force is:
(A) Contact force
(C) Muscular force
(B) Non-contact force
(D) None of these
Answer
55. Unit of co-efficient of friction is:
(A) Newton
(B) Newton-Second
(C) Newton-metre
(D) No unit
Answer
56. Limiting friction is directly proportional to
(A) Normal reaction
(B) Kinetic force of friction
(C) Area of the surface of contact
(D) None of these
Answer
57. Which frictional force is lowest:
(A) Sliding friction
(B) Rolling friction
(C) Static friction
(D) Both (A) and (B)
Answer
58. The tangent of the angle of friction is numerically equal to:
(A) Co-efficient of kinetic friction
(B) Static friction
(C) Co-efficient of static friction
(D) Normal reaction
Answer
59. What are various methods of reducing friction?
(A) Polishing the surface
(B) Lubrication
(C) Both (A) and (B)
(D) None of these
Answer
60. It is difficult to walk on a slippery road. Sand was thrown on the slippery road so that people can walk easily on the road. When sand is thrown on the road:
(A) Force of friction decreases
(B) Force of friction increases
(C) Force of friction is not affected
(D) Road look good
Answer
61. Rolling friction is:
(A) Less then sliding friction
(B) More than sliding friction
(C) Equal to sliding friction
(D) None of these
Answer
62. The component of the contact force parallel to the surface in contact is known as:
(A) Limiting force of friction
(B) Cause of friction
(C) Friction
(D) None of these
Answer
63. Co-efficient of kinetic reaction is:
(A) Always equal to co-efficient of static friction
(B) Less than co-efficient of static friction
(C) More than co-efficient of static friction
(D) None of these
Answer
64. Lubrication is used to:
(A) Increase the friction
(B) Both (A) and (B)
(C) Decrease the friction
(D) None of these
Answer
65. The force of friction is maximum wlien the surface
(A) Is on the point of motion
(B) Is at rest
(C) Is moving
(D) All of these
Answer
66. If a book is moving towards left, friction will act towards
(A) Down
(B) Right
(C) Up
(D) Left
Answer
67. It always opposes relative motion between two surfaces in contact:
(A) Displacement
(B) Tension
(C) Friction
(D) Strain
Answer
68. Friction is a/an
(A) Evil
(B) Foe
(C) Both (A) and (B)
(D) None
Answer
69. It is difficult to walk on any oily floor because:
(B) There is more resistance
(A) Floor, gets spoiled
(C) Force of friction is high
(D) Force of friction is very less
Answer
70. The force of friction is equal to
(A) µR/2
(B) µR/3
(C) 2µR
(D) µR
Answer
71. If 2N force is needed to move a block of mass 2kg with a constant speed over the horizontal surface. What is the coefficient of kinetic energy” (Take g = 10ms ¹)
(A) 0.1
(B) 10
(C) 1
(D) 100
Answer
72. The static friction:
(A) Remain the same with increase in the applied force
(B) Decreases with increase in the applied force
(C) Increases with the increase in the applied force
(D) Increases with decrease in the applied force
Answer
73. The electrostatic forces of alteration between the nucleus and an electron provides the necessary!
(A) Centripetal force
(B) Centrifugal force
(C) Gravitation force
(D) Both (A) and (B)
Answer
74. Which force is needed for circular motion?
(A) Centripetal force
(B) Centrifugal force
(C) Both (A) and(B)
(D) None of these
Answer
75. When moving along a curved path be:
(A) Lean inwards
(B) Lean outwards
(C) Is still
(D) Lean sideways
Answer
76. A trail has to negotiate a curve of radius 400 m. By how much should the patter radius rail be raised with respect to inner rail for speed of 48 km/h. The distance between the rails is Im.
(A) 0.02 m
(B) 0.045 m
(C) 0.40 m
(D) 0.02 m
Answer
77. A cyclists bends while taking turn to
(A) Reduce friction
(B) Reduce apparent weight
(C) Generate required centripetal force
(D) Reduce speed
Answer
78. A body is moving in a vertical circular motion. Which one of the following forces does it not experience?
(A) Force of gravity
(B) Centripetal force
(C) Normal reaction force
(D) Centrifugal force
Answer
79. A body of weight 20 N, mass 2 kg is moving in vertical circular motion with the help of a string of radius 1 m and with a velocity of 2 m/s. What is the tension in the string at the lowest point?
(A) 28 N
(B) 8 N
(C) 20 N
(D) 15 N
Answer
80. A body of weight 20 N, mass 2 kg is moving in vertical circular motion with the help of a string of radius 1 m and with a velocity of 5 m/s. What is the tension in the string at the highest point?
(A) 30 N
(B) 50 N
(C) 20 N
(D) 25 N
Answer
81. A body of weight 20 N, mass 2 kg is moving in vertical circular motion with the help of a string of radius 1 m and with a velocity of 5 m/s. What is the tension in the string when is horizontal?
(A) 30 N
(B) 20 N
(C) 50 N
(D) 25 N
Answer
82. Which one of the following devices acts on the principle of circular motion?
(A) Screw Gauge
(B) Centrifuge
(C) Vernier calipers
(D) Ruler
Answer
83. At which position in vertical circular motion is the tension in the string minimum?
(A) At the highest position
(B) At the lowest position
(C) When the string is horizontal
(D) At an angle of 35° from the horizontal
Answer
84. In Uniform circular motion, the angle between centripetal 10 force and velocity of a particle is
(Α) π/2
(Β) π
(C) π 14
(D) 0
Answer
85. A particle is acted upon by a force of constant magnitude which is always perpendicular to the velocity of the particle The motion of the particle takes place in a horizontal plane Then it follows that
(A) its velocity is constant
(B) its acceleration is constant
(C) its kinetic energy is constant
(D) its linear momentum is constant
Answer
86. The maximum safe speed for a vehicle taking a turn on a curved banked road, does not depend upon
(A) acceleration due to gravity
(B) mass of the vehicle
(C) angle of inclination with the horizontal
(D) radius of curvature of the track
Answer
87. A body is moving along a circular path with variable speed It has
(A) a radial acceleration
(B) a tangential acceleration
(C) zero acceleration
(D) both tangential and radial accelerations
Answer
88. What is the smallest radius of a curve on a horizontal road. at which a cyclist can travel if his speed is 36 km/hour and the angle of inclination is 45°? (g = 10 m/s²)
(A) 25 m
(B) 20 m
(C) 15 m
(D) 10 m
Answer
89. A motor cyclist loops a vertical circular loop of diameter 18 m, without dropping down, even at the highest point of the loop. What should be his minimum speed at the lowest point of the loop?
(A) 10 m/s
(B) 21 m/s
(C) 16 m/s
(D) 30 m/s
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