Assertion (A): | The center of mass of an isolated system of particles remains at rest if it is initially at rest. |
Reason (R): | Internal forces acting within a system cannot change the velocity of the center of mass which is proportional to the total momentum of the system. |
1. | (A) is True but (R) is False. |
2. | (A) is False but (R) is True. |
3. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
4. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
Given below are two statements:
Assertion (A): | Angular momentum of an isolated system of particles is conserved. |
Reason (R): | The net torque on an isolated system of particles is zero and the rate of change of angular momentum equals the torque. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
Assertion (A): | If the sun were to 'suddenly' be removed, then the earth would continue to move around in its orbit. |
Reason (R): | Angular momentum of a system of particles is conserved when there is no external torque. |
1. | Both (A) and (R) are True and (R) is the correct explanation of (A). |
2. | Both (A) and (R) are True but (R) is not the correct explanation of (A). |
3. | (A) is True but (R) is False. |
4. | (A) is False but (R) is True. |
A. | \(a_{cm}=\dfrac{F_1-F_2}{m+M},\) if there is no friction acting between \(m\) and \(M\) |
B. | \(a_{cm}=\dfrac{F_1-F_2}{m+M},\) if there is static friction between \(m\) and \(M\) |
C. | \(a_{cm}=\dfrac{F_1-F_2}{m+M},\) in all situations |
1. | only (A) is true. |
2. | only (B) is true. |
3. | (C) is true. |
4. | (A), (B) are true but (C) is false. |
P. | Momentum of the system is conserved. |
Q. | Kinetic energy of the system does not change after the collision. |
R. | Angular momentum of the system is conserved. |
A: | A body is in translational equilibrium if the net force on it is zero. |
B: | A body is in rotational equilibrium if the net torque about any point is zero. |
1. | (A) only |
2. | (B) only |
3. | both (A) and (B) |
4. | neither (A) nor (B) |
Consider the following two statements:
A: | The linear momentum of a system of particles is zero. |
B: | The kinetic energy of a system of particles is zero. |
1. | A implies B and B implies A. |
2. | A does not imply B and B does not imply A. |
3. | A implies B but B does not imply A. |
4. | B implies A but A does not imply B. |
Consider the following two statements:
A: | The linear momentum of the system remains constant. |
B: | The centre of mass of the system remains at rest. |
1. | A implies B and B implies A |
2. | A does not imply B and B does not imply A |
3. | A implies B but B does not imply A |
4. | B implies A but A does not imply B |
Given the following statements:
(a) | The centre of gravity (C.G.) of a body is the point at which the weight of the body acts. |
(b) | If the earth is assumed to have an infinitely large radius, the centre of mass coincides with the centre of gravity. |
(c) | To evaluate the gravitational field intensity due to any body at an external point, the entire mass of the body can be considered to be concentrated at its C.G. |
(d) | The radius of gyration of any body rotating about an axis is the length of the perpendicular dropped from the C.G. of the body to the axis. |
Which one of the following pairs of statements is correct?
1. | (a) and (b) | 2. | (b) and (c) |
3. | (c) and (d) | 4. | (d) and (a) |
With reference to the figure of a cube of edge a and mass m, the following statements are given. (O is the centre of the cube).
(a) The moment of inertia of the cube about the z-axis is
(b) The moment of inertia of cube about z'-axis is
(c) The moment of inertia of cube about z"-axis is
(d)
Choose the correct statements:
1. (a, c)
2. (a, d)
3. (b, d)
4. (b, c)