9th Class Physics unit 3 MCQs
Chapter 3 MCQs 9th Class Physics
Dynamics:
1. Which of the following is the unit of momentum?
a. Ns
b. Nm
c. Ns-1
d. kgms-2
2. Inertia depends upon:
a. Net force
b. Velocity
c. Force
d. Mass
3. The quantity possessed due to mass and velocity of a body is called:
a. Momentum
b. Acceleration
c. Inertia
d. Velocity
4. Formula of momentum is:
a. P = mv-1
b. M = mv
c. M = mv2
d. P = mv
5. Mathematically momentum is defined as:
a. P = (mv)2
b. P = v/m
c. P = mv
d. P = mv2
6. The product of mass and velocity of a body is called:
a. Work
b. Torque
c. Momentum
d. Force
7. The SI unit of momentum is:
a. Ns-1
b. Nm
c. Ns
d. Kgms-2
8. The branch of mechanics which deals with the study of motion and its causes is called:
a. Momentum
b. Kinematics
c. Rotation
d. Dynamics
9. When a goal keeper stops a ball he applies:
a. Momentum
b. Force
c. Inertia
d. Torque
10. A batsman applies ……… to turn the ball in the different direction.
a. Torque
b. Force
c. Impulse
d. Momentum
11. The concept of inertia was given by
a. Pascal
b. Newton
c. Henry
d. Pascal
12. Momentum of a body is represented by:
a. T
b. M
c. V
d. P
13. In SI, the unit of momentum is Kgms which is equalto
a. Ns-1
b. Nm
c. Ns
d. Kgms-2
14. A string is stretched by two equal and opposite forces 10N each. The tension in the string is:
a. 10N
b. Zero
c. 20N
d. 5N
15. The mass of a body
a. Decreases when moving with high velocity
b. Decreases when accelerated
c. Increases when accelerated
d. None of these
16. Two bodies of masses m and m attached to the ends of an inextensible string passing over a frictionless pulley such that both move vertically. The acceleration of a bodies is:
a. 1+m2m1-m2g
b. m1×m2m1+m2g
c. m1m2m1+m2g
d. 1-m2m1+m2g
17. When horse pulls a cart, the action is on the?
a. Horse
b. Cart
c. Earth and cart
d. Earth
18. A boy jumps out of a moving bus. There is a danger for him to fall
a. In the direction of motion
b. Towards the moving bus
c. Opposite to the direction of motion
d. Away from the bus
19. Newton’s first law of motion is valid only in the absence of:
a. Net force
b. Momentum
c. Force
d. Friction
20. Which of the following relation is correct?
a. F = m/a
b. F = m-a
c. F = a/m
d. F = ma
21. A mass of 6kg is moving with an acceleration of 2ms . Force acting on it is:
a. 8 N
b. 3 N
c. 12 N
d. 4 N
22. Weight ‘w’ is equal to:
a. W=gm
b. w=mg
c. W=1mg
d. W=2mg
23. The unit of weight in system international is:
a. Pound
b. Dyne
c. Newton
d. Kg
24. How much acceleration is produced by a force of 100 N in mass of 50 kg?
a. 0.05 ms-2
b. 0.5 ms-2
c. 2 ms-2
d. 20 ms-2
25. 1 Newton is equal to:
a. 1 kgm-1s-1
b. 1 kgms-2
c. 1kg-1m-1s-1
d. 1 kgms
26. The weight of a body is 147 N. Its mass will be:
a. 0.147 kg
b. 1.47 kg
c. 1.47 kg
d. 14.7 kg
27. The force produces an acceleration of 10 ms in a body of mass 5 kg. The value of force is:
a. 30 N
b. 2 N
c. 50 N
d. 20 N
29. Complete the equation: Pf-Pit
a. T
b. F
c. M
d. S
30. According to law of conservation of momentum:
a. v=-mvM
b. v=mMv
c. v=Mm
d. v=-mvM
31. The resultant of all the forces acting on a body is called:
a. Sum of forces
b. Resultant force
c. Sum of forces
d. Net Force
32. Newton’s first law of motion is related to the ……… property of matter:
a. Non inertial
b. Massive
c. Moving
d. Inertial
33. When a bus takes a sharp turn, passengers fall in the outward direction due to:
a. Inertia
b. Mass
c. Jerk
d. Weight
34. When the driver suddenly applies the brakes, the passengers fall in the ……… direction due to inertia:
a. Left
b. Forward
c. Right
d. Backward
35. Newton’s first law of motion is also known as:
a. Law of gravitation
b. Law of straight line
c. Law of momentum
d. Law of inertia
36. In the second law of motion, acceleration is directly proportional to:
a. Time
b. Force
c. Velocity
d. Mass
37. In the second law of motion, acceleration is inversely proportional to:
a. Time
b. Force
c. Velocity
d. Mass
38. Find the acceleration produced in a body by a force of 20N in a mass of 8kg:
a. 4.5 ms-2
b. 2.5 ms-2
c. 5.5 ms-2
d. 3.5 ms-2
39. Mass and weight are ……… quantities:
a. Congruent
b. Same
c. Equal
d. Different
40. Mass is measured by:
a. Stop watch
b. Ordinary balance
c. Thermometer
d. Spring Balance
41. Weight is measured by:
a. Stop watch
b. Ordinary balance
c. Thermometer
d. Spring balance
42. Mass is a ……… quantity:
a. Derived
b. Scalar
c. Vector
d. None
43. Weight is a ……… quantity:
a. Base
b. Scalar
c. Vector
d. None
44. Quantity of matter in a substance is called:
a. Density
b. Mass
c. Volume
d. Weight
45. The unit of mass is:
a. Newton
b. Dyne
c. Gram
d. Kilogram
46. The mass of a body remains ……… at every place:
a. Changed
b. Variable
c. Zero
d. Constant
47. Application of 3 law of motion is:
a. Book lying on a table
b. Rocket
c. Air filled balloon
d. All
48. An isolated system is a group of bodies on which no ……… force acts:
a. Net
b. Internal
c. Total
d. External
49. When a bullet is fired, the gun recoils a little as compared to the speed of bullet, it is because:
a. To conserve the momentum
b. Large mass of gun
c. Recoiling is in the backward direction
d. None
50. When two interacting balls colloid, they interchange their ………:
a. Torque
b. Mess
c. Velocity
d. Momentum
51. Two bodies are attached to the ends of a string that passes over a frictionless pulley. Then the tension “T” is equal to:
a. m1+m2m1-m2g
b. m1m2m1+m2g
c. 2m1m2m1+m2g
d. m1m1+m2g
52. Which of the following material lowers friction when pushed between metal plates?
a. Air
b. Water
c. Oil
d. Fine marble powder
53. The force that opposes the motion of moving objects is:
a. Friction
b. Weight
c. Momentum
d. Action
54. The maximum value of friction is called:
a. Limiting friction
b. Cold welds
c. Kinetic friction
d. Normal reaction
55. Coefficient of friction is equal to:
a. R/Fs
b. Fs/R
c. Fs+R
d. FsR
56. Coefficient of friction between glass and glass is:
a. 0.8
b. 0.9
c. 0.2
d. 1.0
57. The value of coefficient of friction between steel andsteel is:
a. 0.9
b. 0.05
c. 0.8
d. 0.09
58. Coefficient of friction between tyre and dry road is
a. 0.05
b. 0.6
c. 0.2
d. 1.0
59. Coefficient of friction between the tyre and road is:
a. 0.8
b. 0.2
c. 1
d. 0.6
60. Coefficient of friction between the ice and wood is:
a. 0.2
b. 0.29
c. 1.0
d. 0.05
61. Coefficient of friction between the iron and iron is:
a. 0.8
b. 0.9
c. 1.0
d. 0.62
62. The co efficient of friction is represented by:
a. n
b. μ
c. N
d. o
63. We need ……… to walk on the ground:
a. Resistance
b. Force
c. Pressure
d. Friction
64. The joining points between two sliding surfaces arecalled:
a. Cold welds
b. Interacting points
c. Contact points
d. None
65. The factors affecting friction are:
a. Four
b. Two
c. Five
d. Three
66. The wheels of the moving vehicle have …… velocity components:
a. Four
b. Two
c. Five
d. Three
67. In order to change sliding friction into rolling friction,we use:
a. Wheels
b. Ball bearings
c. Roller bearings
d. All
68. On which surface it is easy for the tyre to roll over?
a. Both
b. Rough
c. Smooth
d. None
69. Slippery road provides ……… friction:
a. Enough
b. Less
c. Rolling
d. Greater
70. Applying brakes too strongly will increase the chanceof:
a. Rolling
b. Friction
c. Sliding
d. Skidding
71. Making the sliding surfaces smooth is a method of:
a. Rolling friction
b. Increasing friction
c. Reducing friction
d. None
72. The force required to move the car in a curved path is:
a. Gravitational force
b. Centrifugal force
c. Centripetal force
d. Tension
73. Which force rotates the body in a circle?
a. Centripetal force
b. Magnetic force
c. Centrifugal force
d. Gravitational force
74. The motion of a body in a circular path is called:
a. Random motion
b. Rotatory motion
c. Centripetal force
d. Circular motion
75. The force which moves the body out the circle iscalled:
a. Rotatory motion
b. Centripetal force
c. Tangential motion
d. Centrifugal force
76. The formula of centripetal force is:
a. Fc=m2vr
b. Fc=m2vr
c. Fc=m2vr2
d. Fc=mv2r
77. Banking of road provides:
a. Rotatory force
b. Centripetal force
c. Circular motion
d. Centrifugal force
78. The dryer of washing machine works on the principleof:
a. Circular motion
b. Centrifuge machine
c. Rotatory motion
d. Centripetal force
79. Cream is ……… than the other components of themilk:
a. Upper
b. Denser
c. Lower
d. Lighter
80. In the cream separator the heavier contents of the milk move in the ……… direction:
a. Left side
b. Inward
c. Right side
d. Outward
81. The SI unit of centripetal force is:
a. Dyne
b. Kg
c. ms-1
d. N
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