Class 11 Physics MCQ Chapter 7 System of Particles and Rotational Motion
Are you searching for Class 11 Physics MCQ Chapter 7 System of Particles and Rotational Motion English Medium? Then this article is an excellent study resource for AHSEC Higher Secondary First Year students. Here, you will find important multiple-choice questions (MCQs) with answers that will help you prepare effectively for your Physics examinations.
The chapter System of Particles and Rotational Motion introduces students to the motion of objects that rotate about an axis and the behavior of systems consisting of multiple particles. Important topics include the center of mass, moment of force (torque), angular momentum, equilibrium of rigid bodies, moment of inertia, and rotational dynamics. These concepts are essential for understanding the mechanics of rotating bodies and many real-world physical systems.
The MCQs provided here are based on the latest AHSEC syllabus and examination pattern. They are carefully designed to help students revise key concepts, improve analytical thinking, and practice exam-oriented objective questions. Regular practice can strengthen conceptual understanding and improve performance in examinations.
Whether you are preparing for class tests, annual examinations, or the AHSEC HS First Year Final Examination, these MCQ solutions will help you revise the chapter efficiently and score higher marks in Physics.
Part I
System of Particles and Rotational Motion
VSA & MCQs
I. Very Short Answer (VSA) Questions with Answers
Q. What is a system of particles?
Ans: A collection of two or more particles considered together is called a system of particles.
Q. What is the centre of mass?
Ans: The point where the entire mass of a system appears to be concentrated.
Q. What is translational motion?
Ans: Motion in which all particles of a body move equal distances in the same direction.
Q. What is rotational motion?
Ans: Motion in which a body rotates about a fixed axis.
Q. What is torque?
Ans: Torque is the turning effect of a force.
Q. What is angular displacement?
Ans: The angle through which a body rotates about an axis.
Q. What is angular velocity?
Ans: Rate of change of angular displacement with time.
Q. What is angular acceleration?
Ans: Rate of change of angular velocity with time.
Q. What is the moment of inertia?
Ans: The rotational analogue of mass that measures resistance to rotational motion.
Q. What is the radius of gyration?
Ans: The distance from the axis at which the entire mass may be assumed concentrated.
Q. What is the equilibrium of a rigid body?
Ans: A rigid body is in equilibrium when the net force and the net torque are zero.
Q. State the law of conservation of angular momentum.
Ans: Angular momentum remains constant when no external torque acts on the system.
Q. What is rolling motion?
Ans: Motion in which a body rotates as well as translates.
Q. What is centripetal force?
Ans: The force acting towards the centre of circular motion.
Q. What is a rigid body?
Ans: A body whose shape and size do not change under applied force.
Q. Define lever arm.
Ans: The perpendicular distance between the axis of rotation and the line of action of the force.
Q. What is static equilibrium?
Ans: Equilibrium of a body at rest.
Q. What is dynamic equilibrium?
Ans: Equilibrium of a moving body with constant velocity.
Q. What is the SI unit of torque?
Ans: Newton metre (N m).
Q. What happens to angular momentum when external torque is zero?
Ans: Angular momentum remains conserved.
Q. The turning effect of force is called:
(a) Momentum
(b) Torque
(c) Friction
(d) Pressure
Ans: (b) Torque
Q. The SI unit of torque is:
(a) Joule
(b) Newton
(c) Newton metre
(d) Watt
Ans: (c) Newton metre
Q. Moment of inertia depends upon:
(a) Mass distribution
(b) Velocity
(c) Temperature
(d) Pressure
Ans: (a) Mass distribution
Q. The rotational analogue of force is:
(a) Work
(b) Torque
(c) Momentum
(d) Power
Ans: (b) Torque
Q. Angular momentum is conserved when:
(a) External force is zero
(b) External torque is zero
(c) Velocity is constant
(d) Acceleration is zero
Ans: (b) External torque is zero
Q. Which quantity is conserved in rotational motion without external torque?
(a) Force
(b) Energy
(c) Angular momentum
(d) Velocity
Ans: (c) Angular momentum
Q. Which motion involves both translation and rotation?
(a) Circular motion
(b) Projectile motion
(c) Rolling motion
(d) Oscillatory motion
Ans: (c) Rolling motion
Q. The centre of mass of a uniform ring lies at:
(a) Circumference
(b) Radius
(c) Centre
(d) Outside the ring
Ans: (c) Centre
Q. Radius of gyration depends upon:
(a) Shape of body
(b) Temperature
(c) Velocity
(d) Force only
Ans: (a) Shape of body
Q. Which quantity is a vector?
(a) Torque
(b) Work
(c) Power
(d) Energy
Ans: (a) Torque
Q. In equilibrium, net torque is:
(a) Maximum
(b) Minimum
(c) Zero
(d) Infinite
Ans: (c) Zero
Q. A dancer spins faster when she folds her arms because:
(a) Angular momentum decreases
(b) The moment of inertia decreases
(c) Torque increases
(d) Velocity decreases
Ans: (b) Moment of inertia decreases
Q. Which quantity depends on the axis of rotation?
(a) Mass
(b) Density
(c) Moment of inertia
(d) Volume
Ans: (c) Moment of inertia
Q. The centre of mass of a body may lie:
(a) Only inside the body
(b) Only outside the body
(c) Inside or outside the body
(d) At the surface only
Ans: (c) Inside or outside the body
Q. The product of the moment of inertia and angular velocity gives:
(a) Torque
(b) Angular momentum
(c) Force
(d) Work
Ans: (b) Angular momentum
Q. Which one is not a rotational quantity?
(a) Torque
(b) Angular momentum
(c) Moment of inertia
(d) Pressure
Ans: (d) Pressure
Q. The rotational analogue of mass is:
(a) Torque
(b) Angular momentum
(c) Moment of inertia
(d) Power
Ans: (c) Moment of inertia
Q. In rolling motion without slipping:
(a) Only translation occurs
(b) Only rotation occurs
(c) Both translation and rotation occur
(d) Neither translation nor rotation occurs
Ans: (c) Both translation and rotation occur
Q. The angular momentum of a body rotating with constant speed remains:
(a) Variable
(b) Zero
(c) Constant
(d) Infinite
Ans: (c) Constant
Q. Which physical quantity causes angular acceleration?
(a) Torque
(b) Momentum
(c) Work
(d) Pressure
Ans: (a) Torque
Q. A rigid body means:
(a) Perfectly hard body
(b) Body with fixed shape and size
(c) Flexible body
(d) Weightless body
Ans: (b) Body with fixed shape and size
Q. The centre of mass of two equal masses lies:
(a) Near a heavier mass
(b) Near lighter mass
(c) Midway between them
(d) Outside the system
Ans: (c) Midway between them
Q. Which quantity is conserved in the absence of external torque?
(a) Linear momentum
(b) Force
(c) Angular momentum
(d) Power
Ans: (c) Angular momentum
Q. Torque depends upon:
(a) Force only
(b) Distance only
(c) Force and perpendicular distance
(d) Velocity only
Ans: (c) Force and perpendicular distance
Q. The perpendicular distance between the axis and the force is called:
(a) Radius
(b) Lever arm
(c) Diameter
(d) Torque arm
Ans: (b) Lever arm
Q. Assertion (A): Angular momentum is conserved in the absence of external torque.
Reason (R): External torque changes angular momentum.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Ans: (a) Both A and R are true and R is the correct explanation of A.
Q. Assertion (A): Torque is the rotational analogue of force.
Reason (R): Torque produces angular acceleration.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false, but R is true.
Ans: (a) Both A and R are true, and R is the correct explanation of A.
Q. Assertion (A): A dancer spins faster by folding her arms inward.
Reason (R): Folding arms decreases the moment of inertia.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false, but R is true.
Ans: (a) Both A and R are true, and R is the correct explanation of A.
Q. Assertion (A): The centre of mass may lie outside a body.
Reason (R): Mass distribution determines the centre of mass.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false, but R is true.
Ans: (a) Both A and R are true, and R is the correct explanation of A.
Q. Assertion (A): Rolling motion involves rotational and translational motion.
Reason (R): In rolling motion, the body rotates while moving forward.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false, but R is true.
Ans: (a) Both A and R are true, and R is the correct explanation of A.
Q. Assertion (A): The moment of inertia depends on the axis of rotation.
Reason (R): The distribution of mass changes with the axis.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false, but R is true.
Ans: (a) Both A and R are true, and R is the correct explanation of A.
Q. Assertion (A): Net torque is zero in rotational equilibrium.
Reason (R): Zero net torque prevents angular acceleration.
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false, but R is true.
Ans: (a) Both A and R are true, and R is the correct explanation of A.
