Angular Velocity

Angular Velocity MDCAT MCQs with answers

25 past paper MCQs on Angular Velocity, from the Rotational and Circular Motion unit of MDCAT Physics. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

Read the notes first Practise the unit as a quiz

1.If a wheel turns at $3.0\ \mathrm{rad\,s^{-1}}$, the time it takes to complete one revolution is about: (MDCAT 2022)

  1. 0.67 s
  2. 10 s
  3. 1.3 s
  4. 2.1 s
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Correct answer: (d) 2.1 s

$T=2\pi/\omega=6.28/3.0\approx2.1$ s.

2.An aircraft makes a turn in a horizontal circle of radius 100 m. It is travelling with a velocity of $250\ \mathrm{m\,s^{-1}}$. The angular velocity of the aircraft will be: (MDCAT 2024)

  1. $1.5\ \mathrm{rad\,s^{-1}}$
  2. $2.5\ \mathrm{rad\,s^{-1}}$
  3. $3\ \mathrm{rad\,s^{-1}}$
  4. $3.5\ \mathrm{rad\,s^{-1}}$
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Correct answer: (b) $2.5\ \mathrm{rad\,s^{-1}}$

$\omega=v/r=250/100=2.5\ \mathrm{rad\,s^{-1}}$.

3.The angular speed of the minute hand of a mechanical watch is: (UHS MDCAT 2017)

  1. $\pi/30\,\mathrm{rad\,s^{-1}}$
  2. $\pi\,\mathrm{rad\,min^{-1}}$
  3. $\pi/2\,\mathrm{rad\,min^{-1}}$
  4. none of the above
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Correct answer: (d) none of the above

The minute hand turns $2\pi$ in 60 minutes, so $\omega=\pi/30\,\mathrm{rad\,min^{-1}}$, which is $\pi/1800\,\mathrm{rad\,s^{-1}}$ and is not among the options.

4.If an object is moving anticlockwise along a circular path, in a horizontal plane on a page then the direction of its angular velocity is: (KMU MDCAT 2025)

  1. Tangential to any point on the circle
  2. Towards centre of the circle
  3. Perpendicular to the plane and pointing out of the page
  4. Perpendicular to the plane and pointing into the page
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Correct answer: (c) Perpendicular to the plane and pointing out of the page

By the right hand rule an anticlockwise rotation gives an angular velocity out of the page.

5.Direction of angular velocity can be found by: (NUMS MDCAT 2025)

  1. Right-hand rule
  2. Fleming's left-hand rule
  3. Lenz's law
  4. Faraday's law
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Correct answer: (a) Right-hand rule

Curl the fingers along the rotation and the thumb gives the direction of the angular velocity.

6.An air craft makes a turn in a horizontal circle of radius100m. It is travelling with a velocity of 250m/sec. The angular velocity of the air craft will be: (UHS MDCAT 2024)

  1. 1.5 rad/sec
  2. 2.5 rad/sec
  3. 3 rad/sec
  4. 3.5 rad/sec
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Correct answer: (b) 2.5 rad/sec

$\omega=v/r=250/100$, which is $2.5\,\mathrm{rad\,s^{-1}}$.

7.The velocity of an object moving in a circle is: (NUMS MDCAT 2024)

  1. Constant
  2. Variable
  3. Zero
  4. Negative
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Correct answer: (b) Variable

The direction changes at every point, so the velocity is not constant even at constant speed.

8.Angle swept by minute hand in one minute is: (NUMS MDCAT 2024)

  1. 6°
  2. 36°
  3. 8°
  4. 20°
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Correct answer: (a) 6°

The hand sweeps $360^{\circ}$ in sixty minutes, so $6^{\circ}$ in one.

9.A particle moves in a circle of radius 10m with speed 20 m/s. Find angular velocity: (NUMS MDCAT 2024)

  1. 2 rad/s
  2. 200 rad/s
  3. 20 rad/s
  4. 10 rad/s
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Correct answer: (a) 2 rad/s

$\omega=v/r=20/10$, which is $2\,\mathrm{rad\,s^{-1}}$.

10.If a flywheel is rotating at 3.0 rad/s, the time it takes to complete one revolution is about (UHS MDCAT 2023)

  1. 0.67 s
  2. 1.0 s
  3. 1.3 s
  4. 2.1 s
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Correct answer: (d) 2.1 s

$T=2\pi/\omega=2\pi/3$, about $2.1\,\mathrm{s}$.

11.Which one of the following is the angular velocity of an electric motor if it rotates at 400 rpm? (SZABMU MDCAT 2023)

  1. 51.2 rad/s
  2. 41.9 rad/s
  3. 45.2 rad/s
  4. 38.5 rad/s
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Correct answer: (b) 41.9 rad/s

$400\times2\pi/60$ gives about $41.9\,\mathrm{rad\,s^{-1}}$.

12.Which one of the following is angular speed in radian per hour for daily rotation of our earth? (SZABMU MDCAT 2023)

  1. 2 π
  2. 4 π
  3. π /6
  4. π /12
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Correct answer: (d) π /12

$2\pi$ radians in $24$ hours is $\pi/12$ radians an hour.

13.An electric motor turns at 400 revolutions per minute. Its angular velocity in rad/s will be: (NUMS MDCAT 2023)

  1. 20π/3
  2. 30π/3
  3. 40π/3
  4. 30π/4
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Correct answer: (c) 40π/3

$400\times2\pi/60$ is $40\pi/3\,\mathrm{rad\,s^{-1}}$.

14.An object travelling in a circle at 2 revolutions per second has an angular velocity of: (PMC MDCAT 2022)

  1. 12.9 rad/s
  2. 13.3 rad/s
  3. 12.6 rad/s
  4. 14.6 rad/s
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Correct answer: (c) 12.6 rad/s

$\omega=2\pi f=2\times2\pi$, about $12.6\,\mathrm{rad\,s^{-1}}$.

15.The rotation of the earth in 1 day covers approximately ____ radian angular distance. (PMC MDCAT 2022)

  1. 6.3
  2. 7.3
  3. 10.3
  4. 5.3
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Correct answer: (a) 6.3

A full turn is $2\pi$, about $6.3$ radians.

16.When body moves in a circle _______ always changes: (PMC MDCAT 2022)

  1. Velocity
  2. Acceleration
  3. Mass
  4. Force
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Correct answer: (a) Velocity

The direction changes at every point, so the velocity is never constant.

17.Earth covers its one revolution around the Sun in: (PMC MDCAT 2022)

  1. 24 hours
  2. 7 days
  3. 12 months
  4. 60 minutes
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Correct answer: (c) 12 months

The Earth takes a year, that is twelve months, to go once round the Sun.

18.The earth rotates 360o about its axis in about 24 hours. By how many degrees will it rotate In 2 hours? (PMC MDCAT 2022)

  1. 90
  2. 60
  3. 30
  4. 15
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Correct answer: (c) 30

$360^{\circ}$ in $24$ hours is $15^{\circ}$ an hour, so $30^{\circ}$ in two.

19.A rotating wheel coincides 12 rev in 4s. find the average angular velocity in rad/sec: (NUMS MDCAT 2022)

  1. 24.6 rad/s
  2. 16.8 rad/s
  3. 10.4 rad/s
  4. 18.8 rad/s
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Correct answer: (d) 18.8 rad/s

$12\times2\pi/4$ is about $18.8\,\mathrm{rad\,s^{-1}}$.

20.One rpm is equal to _____ rad/sec (PMC Practice 2021)

  1. 2
  2. 1.5
  3. 2.5
  4. 0.105
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Correct answer: (d) 0.105

One revolution a minute is $2\pi/60$, about $0.105\,\mathrm{rad\,s^{-1}}$.

21.If a rotating body is moving anti-clockwise, the direction of angular velocity is: (PMC Practice 2021)

  1. Towards the centre
  2. Along the linear velocity
  3. Away from the centre
  4. Perpendicular to both radius and linear velocity
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Correct answer: (d) Perpendicular to both radius and linear velocity

The angular velocity lies along the axis, at right angles to both the radius and the linear velocity.

22.If an object is undergoing an orbital motion around another object it is called? (PMC Practice 2021)

  1. Revolution
  2. Rotation
  3. Both of them
  4. None of them
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Correct answer: (a) Revolution

A body going round another is said to revolve; turning on its own axis is rotation.

23.When a body moves in a circle, the angle between its linear velocity and angular velocity is always? (PMC Practice 2021)

  1. 180°
  2. 0°
  3. 90°
  4. 45°
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Correct answer: (c) 90°

The angular velocity lies along the axis and the linear velocity along the tangent, so they are at right angles.

24.The earth rotates on its axis once a day. Suppose, by some process the earth contracts so that it’s radius is only half as large as at present, then how long the earth will take to complete it’s rotation? (PMC MDCAT 2020)

  1. 24 hours
  2. 18 hours
  3. 6 hours
  4. 12 hours
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Correct answer: (c) 6 hours

Angular momentum is conserved and $I$ goes as $r^2$, so a half radius spins four times as fast, in six hours.

25.A wheel starts rotating from result 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: (UHS MDCAT 2018)

  1. 4 rad
  2. 9 rad
  3. 12 rad
  4. 7 rad
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Correct answer: (b) 9 rad

$\omega^2=2\alpha\theta$ gives $36=4\theta$, so $\theta$ is $9\,\mathrm{rad}$.

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