Online Test on System of Particles and Rotational Motion For Class 11 Physics

On this page find NCERT MCQ Questions for Class 11 Physics Chapter 7 System of Particles and Rotational Motion with Answers. These MCQ Questions for Class 11 Physics with Answers were created using the most recent exam pattern. We have included System of Particles and Rotational Motion Class 11 Physics MCQs Questions with Answers to assist students in fully understanding the concept.

A rigid body is one with particles that are at a fixed distance from each other and remain constant. The geometrical centre is the location of the centre of mass in every regular body. The net torque also produces the turning motion in the rigid body.

Concepts used in describing motion of system of particles and rotation are

• Concepts such as the centre of mass,
• torque, angular momentum,
• conservation of angular momentum,
• the radius of gyration, and
• theorems related to perpendicular and parallel axes

We have tried to cover questions from all these topics

MCQs for Class 11 Physics Chapter 7 System of Particles and Rotational Motion

General Instructions

1. Your test contains multiple-choice questions with only one answer type of questions. There are a total of 25 questions
2. This is a 60 min test. Please make sure you complete it in the stipulated time
3. You can finish this test any time using the ‘Submit’ button.

• <<
• 1
• 2
• 3
• 4
• 5
• 6
• 7
• 8
• 9
• 10
• 11
• 12
• 13
• 14
• 15
• 16
• 17
• 18
• 19
• 20
• 21
• 22
• 23
• 24
• 25
• >>

1. If the resultant of all external forces acting on a system of particles is zero, then from an inertial frame one can surely say that

Linear momentum of the system does not change in time

Kinetic energy of the system does not change in time.

Angular momentum of the system does not change in time.

Potential energy of the system does not change in time.

2. This question contains Statement – 1 (assertion) and statement – 2 (reason). Of these statements, mark correct choice if
Statement 1: If there is no external torque on a body about its center of mass, then the velocity of the center of mass remains constant.
Statement 2: The linear momentum of an isolated system remains constant.

Statement - 1 and 2 are true and statement - 2 is a correct explanation of statement - 1

Statement -1 and 2 are true and statement - 2 is not a correct explanation of statement - 1

Statement – 1 is true and Statement - 2 is false.

Statement – 1 is false, statement – 2 is true.

3. Four-point masses, each of value $m$, are placed at the corners of a square $ABCD$ of side $l$. The moment of inertia of this system about an axis passing through $A$ and parallel to $BD$ is

$3ml^2$

$ml^2$

$2ml^2$

$\sqrt3ml^2$

4. Moment of inertia of a circular wire of mass M and radius R about its diameter is

$\frac{1}{2}MR^2$

$\frac{1}{4}MR^2$

$2MR^2$

$MR^2$

5. Initial angular velocity of a circular disc of mass $M$ is $\omega_1$. Then, two small spheres of mass $m$ are attached gently to two diametrically opposite points on the edge of the disc. What is the final angular velocity of the disc?

$\frac{M+m}{M}\omega_1$

$\frac{M}{M+m}\omega_1$

$\frac{M}{M+4m}\omega_1$

$\frac{M}{M+2m}\omega_1$

6. A thin horizontal circular disc is rotating about a vertical axis passing through its center. An insect is at rest at a point near the rim of the disc. The insect now moves along the diameter of the disc to reach its other end. During the journey of the insect, the angular speed of the disc,

Remains unchanged

Continuously decreases

Continuously increases

First increases and then decreases

7. The dimensions of angular momentum are

$\left[MLT^{-2}\right]$

$\left[ML^2T^{-1}\right]$

$\left[ML^2T^{-2}\right]$

$\left[ML^2T\right]$

8. The torque $\tau$ on a body about a given point is found to be equal to $\vec{A}\times\vec{L}$, where $\vec{A}$ is a constant vector and $\vec{L}$ is the angular momentum of the body about that point. From this, it follows that

$\frac{d\vec{L}}{dt}$ is perpendicular to $\vec{L}$ at all instants of time

The component of $\vec{L}$ in the direction of $\vec{A}$ does not change with time

The magnitude $\vec{L}$ does not change with time.

all the above

9. A solid sphere of radius $r$ is rolling with velocity $v$ on a smooth plane. The total Kinetic energy of the sphere is

$\frac{7}{10}mv^2$

$\frac{3}{4}mv^2$

$\frac{1}{2}mv^2$

$\frac{1}{4}mv^2$

10. A coin of mass 4.8 Kg and radius one meter is rolling on a horizontal surface without sliding with angular velocity 600 rotations/min. What is total Kinetic energy of the coin?

$360 J$

$1400\pi^2J$

$4000\pi^2J$

$600\pi^2J$

11. Two spheres of masses $M$ and $2M$ are initially at rest at a distance $R$ apart. Due to mutual force of attraction, they approach each other. When they are at separation $R/2$ the acceleration of their center of mass would be

$0$

$g$

$3g$

$12g$

12. In the following question, a statement of assertion is followed by a statement of reason. Mark the correct choice as
Assertion: There are very small sporadic changes in the period of rotation of the earth.
Reason: Shifting of large masses in the earth’s atmosphere produces a change in the moment of inertia of the earth causing its period of rotation to change.

If both assertion ad reason are true and reason is the correct explanation of assertion.

If both assertion and reason are true and reason is not correct explanation of assertion.

If assertion is true, but reason is false

If both assertion and reason are false

13. In the following question, a statement of assertion is followed by a statement of reason. Mark the correct choice as
Assertion: If polar ice melts, days will be longer.
Reason: Moment of inertia decreases and thus angular velocity increases.

If both assertion ad reason are true and reason is the correct explanation of assertion.

If both assertion and reason are true and reason is not correct explanation of assertion.

If assertion is true, but reason is false

If both assertion and reason are false

14. In the following question, a statement of assertion is followed by a statement of reason. Mark the correct choice as
Assertion: The size and the shape of the rigid body remains unaffected under the effect of external forces.
Reason: The distance between two particles remains constant in a rigid body

If both assertion ad reason are true and reason is the correct explanation of assertion.

If both assertion and reason are true and reason is not correct explanation of assertion.

If assertion is true, but reason is false

If both assertion and reason are false

15. In the following question, a statement of assertion is followed by a statement of reason. Mark the correct choice as
Assertion: A wheel moving down a perfectly frictionless inclined plane will undergo slipping (not rolling motion).
Reason: For perfect rolling motion, work done against friction is zero

If both assertion ad reason are true and reason is the correct explanation of assertion.

If both assertion and reason are true and reason is not correct explanation of assertion.

If assertion is true, but reason is false

If both assertion and reason are false

16. A disc is rolling and the velocity of its center of mass is.
Which one will be correct?

The velocity of the highest point is $2v_{cm}$ and the point of contact is zero.

The velocity of the highest point is $v_{cm}$ and the point of contact is v_{cm}

The velocity of the highest point is ${2v}_{cm}$ and the point of contact is v_{cm}

The velocity of the highest point is ${2v}_{cm}$ and the point of contact is ${2v}_{cm}$

17. Identify the vector quantity among the following

distance

angular momentum

heat

energy

18. Find the torque of the force $\vec{F}=-3\hat{i}+\hat{j}+5\hat{k}N$ acting at the point $\vec{r}=7\hat{i}+3\hat{j}+\hat{k}$

$-21\hat{i}+4\hat{j}+4\hat{k}$

$-14\hat{i}+34\hat{j}-16\hat{k}$

$14\hat{i}-38\hat{j}+16\hat{k}$

$4\hat{i}+4\hat{j}+6\hat{k}$

19. A circular disc is to be made by using iron and aluminum so that it acquired maximum moment of inertia about geometrical axis. It is possible with

Aluminum interior and iron surround to it

iron interior and aluminum surround to it

using iron and aluminum layers in alternate order

sheet of iron is used at both external surfaces and aluminum sheet as the internal layer

20. A ring of mass m and radius r rotates about an axis passing through its center and perpendicular to its plane with angular velocity $\omega$. Its kinetic energy is

$\frac{1}{2}mr^2\omega^2$

$mr\omega^2$

$mr^2\omega^2$

$ \frac{1}{2}mr\omega^2$

21. The ratio of radii of gyration of a circular disc about a tangential axis in the plane of the disc and of a circular ring of the same radius about a tangential axis in the plane of the ring is

$2:3$

$2:1$

$\sqrt5:\sqrt6$

$1:\sqrt2$

22. The ratio of the radii of gyration of a circular disc to that of circular ring, each of same mass, each of same mass and same radius about their axes is

$\sqrt3:\sqrt2$

$1:\sqrt2$

$\sqrt2:1$

$\sqrt2:\sqrt3$

23. A disc is rotating with angular speed \omega. If the child sits on it, what is conserved

linear momentum

angular momentum

kinetic energy

potential energy

24. A solid sphere, disc and solid cylinder all of the same mass and made of same material are allowed to roll down (from rest) on the inclined plane, then

solid sphere reaches the bottom first

solid cylinder reaches the bottom first

disc will reach the bottom first

all reach the bottom at the same time

25. The moment of inertia of a thin uniform rod of mass $M$ and length $L$ about an axis passing through its mid-point and perpendicular to its length is $I_0$. Its moment of inertia about an axis passing through one of its ends and perpendicular to its length is

$I_0+\frac{ML^2}{2}$

$I_0+\frac{ML^2}{4}$

$I_0+2ML^2$

$I_0+ML^2$

 Loading...