Physics Chapter 3 Entry test MCQs
51. The direction of centripetal force is
a. Away from center
b. Towards the center
c. Along the axis of rotation
d. Along the tangential velocity
52. A car of mass 1000kg traveling at 40ms-1 rounds a curve of radius 100m. what is the Fc
a. 1.6 x104 N
b. 100 N
c. 8 x104 N
d. 1.6 x106 N
53. If the radius of the circular path of a moving body is half without changing speed of rotation then the Fc becomes
a. Doubled
b. Half
c. One forth
d. One third
54. A stone of mass 250 g is tied to the end of a string of length 1.0 m. It is whirled in a horizontal circle with a frequency of 30 rev./min. What is the tension in the string?
a. π2/2 N
b. π2/4 N
c. 2π2 N
d. π2 N
55. A particle of mass m is executing uniform circular motion on a path of radius r. If p is the magnitude of its linear momentum. The radial force acting on the particle is
a. p2/r m
b. mp2 / r
c. pmr
d. rm/p
56. A stone ties to the end of a string Im long is whirled in a horizontal circle with a constant speed. If the stone makes 22 revolution in 44 seconds, what is the magnitude and direction of acceleration of the stone
a. π2 ms-2 and direction along the radius away from the centre
b. π2/4 ms-2 and direction along the radius towards the centre
c. π2 ms-2 and direction along the tangent to the circle
d. π2 ms-2 and direction along the radius towards the centre
PAST PAPER MCQS
57. The force required to bend the normally straight path of a particle into a circular path is called————-force.
a. Bending
b. Traveling
c. Centripetal
d. Centrifugal
58. Linear velocity or tangential velocity of any particle moving in a circular path of radius 2 m with angular velocity 8 rads-¹ will be:
a. 4m s-1
b. 16m s-1
c. 6m s-1
d. 10m s-1
59. A wheel of radius 1 m covers an angular displacement of 180. Its linear displacement is
a. π rad
b. 3.14 m
c. 0.157 m
d. 6.28 m
60. When a body moves in a circle the angle between its linear velocity and angular velocity is always:
a. 360°
b. 0°
c. 90°
d. 180°
61. Radian is a unit of angular displacement which can also be measured in degrees. How many radians are equal to one degree?
a. 2π/180
b. 180/π
c. π/57.3
d. π/180
62. The centripetal acceleration of a car travelling constant speed around a frictionless circular track:
a. Has constant direction but varying magnitude
b. Is zero
c. Has varying magnitude and direction
d. Has constant magnitude but varying direction
63. A wheel starts from rest and has an angular acceleration of 4.0 rad/s2 When it has made 10 rev its angular velocity is:
a. 32 rad/s
b. 16 rad/s
c. 250 rad/s
d. 22 rad/s
64. A child riding on a large merry-go-round, travels a distance of 3000m in a circle of diameter 40m. The total angle through which she revolves is:
a. 150 rad
b. 50 rad
c. 314 rad
d. 75 rad
65. The angular velocity for daily rotation of the earth is:
a. π/12 radian hr-1
b. π/3 radian hr-1
c. 12 radian hr-1
d. π/6 radian hr-1
66. A body moves in a circle with increasing angular velocity. At time t= 6sec, the angular velocity is 27rad/s. What is the radius of circle made by the body where linear velocity is 81cm / (s’).
a. 3cm
b. 6cm
c. 7cm
d. 9cm
67. Angular speed of minutes hand of mechanical watch is:
a. π rad min
b. π/30 rad min-1
c. π/ 2 rad min-1
d. None of these
68. A body is moving in a circular path with constant speed. The magnitude of tangential and centripetal acceleration are:
69. A centripetal force F acts on a body moving with angular speed . If the angular speed is tripled, then the magnitude of centripetal force becomes:
a. 3 F
b. 8F
c. 4 F
d. 9 F
70. A fly wheels rotates at a constant speed of 3000 rpm (rev / min) The angle described by the shaft in radian in one second is:
a. 100π
b. 2π
c. 300π
d. 30π
71. A wheel starts rotating from rest with angular acceleration of 2 rads-2 till its angular speed becomes (6 rad) / s. The angular displacement of the wheel will be equal to
a. 9 rad
b. 4 rad
c. 7 rad
d. 12 rad
72. Which of the following gives the relationship between linear velocity and angular velocity?
a. v = rθ
b. v = rω
c. v = sθ
d. v =sω
73. An object is moving along a circular path of radius 4m. What will be its angular displacement if it moves 14m on this circular path?
a. 3.5 radians
b. 5.5 radians
c. 4.5 radians
d. 5.0 radians
74. If during circular motion, tangential velocity of a body becomes double, then centripetal force becomes:
a. Four times
b. Double
c. One fourth
d. One half
75. Under what condition an object will have zero displacement but non zero distance?
a. Random motion
b. Linear motion
c. Oscillation
d. Circular motion
76. 1 radian is equal to
a. 57.3°
b. 57.1°
c. 57.4°
d. 57.2°
77. A 10N force moves a body around a circular path of radius 50 cm. What is work done it completing one revolution?
a. 31.42 J
b. 5J
c. 500 J
d. 0
78. Number of revolutions in 720 degrees.
a. 2 revolutions
b. 4 revolutions
c. 9 revolutions
d. 3 revolutions
79. Car moves in circular path due to
a. Gravitational force
b. Frictional force
c. Centripetal force
d. None
80. Radian is used to measure
a. Small angles
b. Large angles
c. Both
d. None
81. If earth covers 360 degrees in 24 hours, then how many degrees are in two hours
a. 45°
b. 30°
c. 60°
d. 15°
82. Earth completes one revolution in
a. 12 months
b. 24 hours
c. 6 months
d. None