HSSC-I (Class-11) Solved Physics MCQs; Unit-5: Rotational and Circular motion (Baluchistan Textbook Board, Quetta) With Verified Answers:



1. 85.95° degree in terms of a radian is




... Answer is C. `\1 frac {1}{2}`radian
57.3° = 1 rad or 1° = 0.01745 rad


2. What is the circumference of a circle, having a radius of 50 cm?




... Answer is B. 3.14 m
Circumference of circle = 2ã„«r


3. What is the angular velocity of a particle when its frequency is 50 Hz?




... Answer is C. 314 rad s⁻¹
à´§ = 2ã„«f


4. The direction of angular velocity is along;




... Answer is B. Axis of rotation
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5.  Angular speed for annual rotation of Earth in radians per day.




... Answer is C. 2ã„« radian/day
ധ = `\frac {Δθ}{Δt}`= `\frac {2ㄫ rad}{day}` (as Earth completes one rotation in a day)


6. A body moves with constant angular velocity in a circle. The magnitude of angular acceleration is




... Answer is C. Zero
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7. Banking angle does not depend upon the:




... Answer is A. Mass
tanθ = `\frac {v^2}{Rg}`


8. What will happen if the height of an orbit of a satellite from the surface of the earth is increased,




... Answer is B. Angular velocity increases
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9. What is the ratio of translational and rotational kinetic energies of a solid sphere.




... Answer is A. `\frac {1}{2}`
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10. Angular momentum in terms of the moment of inertia is




... Answer is A. Ià´§
 L = Ià´§


11. Which one of the following rolling bodies has 50% translational K.E and 50% rotational K.E.




... Answer is B. Ring
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12. A solid cylinder of mass 20 kg rotates about its axis with an angular velocity of 10 m s⁻¹, a radius of 0.2m. The moment of inertia of the cylinder is




... Answer is D. 0.8 kg m²
I = mr²


13. The condition of weightlessness is (N=Normal Reaction and W is weight)

... Answer is D. N=0
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14.  A sphere is rolling without slipping on a horizontal plane. The ratio of its rotational kinetic energy and translational kinetic energy is




... Answer is B. 2:5
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15. The frequency of artificial gravity is




... Answer is C. `\frac {1}{2ã„«}` `\sqrt frac {R}{g}`
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16.. A particle of mass 100 g starts its motion from rest along a circular path of radius 10 cm. If its velocity becomes 10 m s⁻¹ then its centripetal force is;




... Answer is D. 100 N
Fc = `\frac {mv^2}{r}`


17. Which one of the following is conserved when the torque acting on a system is zero? :




... Answer is B. Angular momentum
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18. Orbital velocity of earth's satellite near the surface is 7 km/s. If the radius of the orbit is 4 times that of Earth's radius, what will be the orbital velocity in that orbit?




... Answer is D. 14 km s⁻¹
v = `\sqrt {gR}`


19. When a parachutist is moving downward with uniform motion then its weight is:




... Answer is C. Remain same
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20. An object of mass 1.5 kg is suspended by a string having tension T = 5 N in a lift. When the lift is moving upward with an acceleration of 2 m s⁻¹ then its apparent weight is:




... Answer is C. 2 N
For downward motion F = T - W or W = T - ma {where F = ma}



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