Free Rotational and Circular Motion MCQs with Answers
521 Rotational and Circular Motion MCQs from Physics, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Angular displacement and angular velocity describe rotation, with angles measured in radians and related to time through angular speed. The connection between angular and linear quantities includes arc length, tangential speed and centripetal acceleration, so circular motion is not confused with motion at constant velocity.
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Read the Rotational and Circular Motion notesFree MDCAT chapter notes with key terms521 questions · page 26 of 27
501. A body Is moving in a circle of radius (r) with a variable speed, the acceleration of the body is:
- A. Centripetal acceleration
- B. Tangential acceleration
- C. Angular acceleration
- D. All of the above
Explanation: Since the magnitude of the speed is not constant, this is a case of non-uniform circular motion and there will be a tangential…
Correct answer: All of the above- A. Torque
- B. Weight
- C. Moment of inertia
- D. Angular momentum
Explanation: Moment of inertia is referred to as the rotational analogue of mass in linear motion.
Correct answer: Moment of inertia- A. Increases
- B. Decreases
- C. Remains constant
- D. Changes direction but not magnitude
Explanation: Angular momentum is a conserved quantity in the absence of external torques.
Correct answer: Remains constant- A. 0.38 kg - m2
- B. 0.54 kg - m2
- C. 0.86 kg - m2
- D. 1.02 kg - m2
Explanation: The correct answer is 1.02 kg - m2. The initial rotational inertia of the disk is 0.70 kg m2.
Correct answer: 1.02 kg - m2- A. Mv2
- B. ½ Mv2
- C. ¼ Mv2
- D. 1/8 Mv2
Explanation: The kinetic energy of the rotating disc can be calculated as:KE = (1/2) I ω^2where I is the moment of inertia and ω is the angular…
Correct answer: ¼ Mv2- A. Mass of an object
- B. Mass of distribution
- C. Angular velocity
- D. Axis of rotation
Explanation: The moment of inertia Iof an object is a measure of its resistance to changes in angular velocity.
Correct answer: Angular velocity507. The speedometer of a car shows 36 km/hr. The angular speed of the wheels having 0.5m radius is:
- A. 5 rad/sec
- B. 10 rad/sec
- C. 15 rad/sec
- D. 20 rad/sec
Explanation: To solve for the angular speed of the wheels, we first need to convert the car's speed from kilometers per hour to meters per second.
Correct answer: 20 rad/sec508. Centrifugal force =
- A. mv^2/r
- B. m^2v/r
- C. mv/r^2
- D. mv2/r
Explanation: Centrifugal force (F_c) is an outward force that arises when an object moves in a circular path.
Correct answer: mv^2/r- A. Angular acceleration
- B. Centripetal acceleration
- C. Tangential acceleration
- D. Translator acceleration
Explanation: Radial acceleration, also known as centripetal acceleration, is the acceleration of an object moving in a circular path towards the center…
Correct answer: Centripetal acceleration- A. 2π radians
- B. π radians
- C. 270 degrees
- D. 180 degrees
Explanation: The circumference covers the entire length of the circle, so the angle subtended by it must be equal to the maximum angle in the circle…
Correct answer: 2π radians- A. 30 degrees
- B. 120 degrees
- C. 180 degrees
- D. 360 degrees
Explanation: In a full hour, the minute hand of a watch completes a 360-degree rotation, which is equivalent to 2π radians.
Correct answer: 30 degrees- A. 180 degrees
- B. 360 degrees
- C. 540 degrees
- D. 720 degrees
Explanation: A full turn around a circle is 360 degrees or 2π radians. For two complete turns, multiply the angle of one turn by 2, resulting in 720…
Correct answer: 720 degrees- A. 2 rad
- B. 1 rad
- C. 2π rad
- D. None of the above
Explanation: When an object is revolving in a circular path with a radius of 2m and it travels along an arc of length 4m, we can calculate the angle…
Correct answer: 2 rad- A. 100
- B. 20π
- C. 0
- D. 20
Explanation: To determine the angle described by the shaft in radians in one second, we first need to convert the rotational speed from revolutions per…
Correct answer: 20π- A. Decrease
- B. Increase
- C. Remain the same
- D. First increase and then decrease
Explanation: According to conservation of Angular Momentum, Iω = constant Hence, when the girl sitting on a bar stool suddenly spreads her hands, then…
Correct answer: Decrease- A. decrease
- B. increase
- C. Remain the same
- D. first increase and then decrease
Explanation: The moment of inertia of girl increases (since the mass of her legs is now farther from the axis of rotation).
Correct answer: decrease- A. π/3 radian hr-1
- B. π/6 radian hr-1
- C. π/12 radian hr-1
- D. 12 radian hr-1
Explanation: The angular velocity (ω) is the scalar measure of rotation rate. In one complete rotation, angular distance travelled is 2π and time is…
Correct answer: π/12 radian hr-1- A. π rad/sec2
- B. 2π rad/sec2
- C. π/2 rad/sec2
- D. None of the above
Explanation: Angular acceleration (α) is defined as the change in angular velocity (ꞷ) per unit time.
Correct answer: None of the above- A. The tangent to the circular path
- B. The axis of rotation
- C. The outward radius
- D. The inward radius
Explanation: When an object rotates, it has an axis around which it spins. The direction of the angular velocity vector is parallel to this axis of…
Correct answer: The axis of rotation- A. π/12 radian/hour
- B. 12π radian/hour
- C. 24π radian/hour
- D. π/24 radian/hour
Explanation: The correct answer is π/12 radian/hour. To find the angular speed in radians, we recognize that one full rotation (2π radians) occurs in…
Correct answer: π/12 radian/hour