Unit 7: System of Particles and Rotational Motion — Online MCQ Test
PHYSICS · CLASS 11 INTERMEDIATE 1 YEAR · Telangana State Board
Practice Unit 7: System of Particles and Rotational Motion with a free chapter-wise online MCQ test.
This chapter covers: Focusing on rigid body dynamics this chapter details center of mass torque angular momentum conservation equations of rotational motion moment of inertia and parallel perpendicular....
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Unit 7: System of Particles and Rotational Motion — Important Questions & Answers
What is the position vector of the centre of mass of a system of particles given by?
- A. Sum of individual position vectors divided by number of particles
- B. Mass-weighted average of the position vectors of all particles
- C. Product of masses and position vectors divided by total mass squared
- D. Vector sum of all forces acting on the system
Answer: B. Mass-weighted average of the position vectors of all particles
The centre of mass is the mass-weighted average position of all particles in the system.
The centre of mass is the mass-weighted average position of all particles in the system.
Which of the following is a vector quantity?
- A. Mass
- B. Moment of inertia
- C. Torque
- D. Moment of inertia about an axis
Answer: C. Torque
Torque has both magnitude and direction, so it is a vector quantity.
Torque has both magnitude and direction, so it is a vector quantity.
A rigid body rotates with constant angular velocity. Which of the following is true?
- A. Angular acceleration is zero
- B. Torque must be non-zero
- C. Moment of inertia becomes zero
- D. Angular momentum is always zero
Answer: A. Angular acceleration is zero
If angular velocity is constant, its rate of change is zero, so angular acceleration is zero.
If angular velocity is constant, its rate of change is zero, so angular acceleration is zero.
Which statement about the moment of inertia of a rigid body is correct?
- A. It depends only on the total mass, not on distribution
- B. It depends on the axis of rotation and mass distribution
- C. It is the same for all axes through the body
- D. It is a scalar independent of position of axis
Answer: B. It depends on the axis of rotation and mass distribution
Moment of inertia depends on how mass is distributed relative to the chosen axis.
Moment of inertia depends on how mass is distributed relative to the chosen axis.
Two equal masses are placed symmetrically at equal distances on opposite sides of the origin along the x-axis. The centre of mass is at:
- A. The point of one of the masses
- B. The midpoint between the masses
- C. A point closer to the heavier mass
- D. Infinity
Answer: B. The midpoint between the masses
For equal masses placed symmetrically, the centre of mass lies exactly at the midpoint.
For equal masses placed symmetrically, the centre of mass lies exactly at the midpoint.