Centre of Mass
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365796 A massless spring of force constant \(1000 {Nm}^{-1}\) is compressed a distance of 20 \(cm\) between discs of 8 \(kg\) and 2 \(kg\) , spring is not attached to discs. The system is given an initial velocity \(3 {~ms}^{-1}\) perpendicular to length of spring as shown in the figure. What is ground frame velocity of 2 \(kg\) block when spring regains its natural length.
supporting img

1 \(1\,m/{s^{ - 1}}\)
2 \(8\,m/{s^{ - 1}}\)
3 \(6\,m/{s^{ - 1}}\)
4 \(5\,m/{s^{ - 1}}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365797 A block of mass \(m\) slides with velocity \(v\) along a frictionless level surface towards a block of mass \(4 m\) initially at rest. The velocity of centre of mass is

1 \(v / 5\)
2 \(v / 4\)
3 \(5 v / 2\)
4 \((4 / 5) v\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365798 Two objects of masses \(300\;g\) and \(700\;g\) posseses velocities \(15\hat i\;m{\rm{/}}s\) and \(4\hat i + 6\hat j\;m{\rm{/}}s\) respectively. The velocity of their centre of mass in \(m{\rm{/}}s\) is

1 \(7 \hat{i}+8 \hat{j}\)
2 \(7.3 \hat{i}+4.2 \hat{j}\)
3 \(5 \hat{i}+4 \hat{j}\)
4 \(2 \hat{i}+6 \hat{j}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365799 Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are \(v_{1}\) and \(v_{2}\) at any instant, then the speed of centre of mass of the system will be:

1 \(v_{1}+v_{2}\)
2 \(v_{1}-v_{2}\)
3 Zero
4 \(\dfrac{v_{1}+v_{2}}{2}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365800 Assertion :
The centre mass of an electron and proton, when released remains at rest.
Reason :
Proton is heavier than electron.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365796 A massless spring of force constant \(1000 {Nm}^{-1}\) is compressed a distance of 20 \(cm\) between discs of 8 \(kg\) and 2 \(kg\) , spring is not attached to discs. The system is given an initial velocity \(3 {~ms}^{-1}\) perpendicular to length of spring as shown in the figure. What is ground frame velocity of 2 \(kg\) block when spring regains its natural length.
supporting img

1 \(1\,m/{s^{ - 1}}\)
2 \(8\,m/{s^{ - 1}}\)
3 \(6\,m/{s^{ - 1}}\)
4 \(5\,m/{s^{ - 1}}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365797 A block of mass \(m\) slides with velocity \(v\) along a frictionless level surface towards a block of mass \(4 m\) initially at rest. The velocity of centre of mass is

1 \(v / 5\)
2 \(v / 4\)
3 \(5 v / 2\)
4 \((4 / 5) v\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365798 Two objects of masses \(300\;g\) and \(700\;g\) posseses velocities \(15\hat i\;m{\rm{/}}s\) and \(4\hat i + 6\hat j\;m{\rm{/}}s\) respectively. The velocity of their centre of mass in \(m{\rm{/}}s\) is

1 \(7 \hat{i}+8 \hat{j}\)
2 \(7.3 \hat{i}+4.2 \hat{j}\)
3 \(5 \hat{i}+4 \hat{j}\)
4 \(2 \hat{i}+6 \hat{j}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365799 Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are \(v_{1}\) and \(v_{2}\) at any instant, then the speed of centre of mass of the system will be:

1 \(v_{1}+v_{2}\)
2 \(v_{1}-v_{2}\)
3 Zero
4 \(\dfrac{v_{1}+v_{2}}{2}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365800 Assertion :
The centre mass of an electron and proton, when released remains at rest.
Reason :
Proton is heavier than electron.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365796 A massless spring of force constant \(1000 {Nm}^{-1}\) is compressed a distance of 20 \(cm\) between discs of 8 \(kg\) and 2 \(kg\) , spring is not attached to discs. The system is given an initial velocity \(3 {~ms}^{-1}\) perpendicular to length of spring as shown in the figure. What is ground frame velocity of 2 \(kg\) block when spring regains its natural length.
supporting img

1 \(1\,m/{s^{ - 1}}\)
2 \(8\,m/{s^{ - 1}}\)
3 \(6\,m/{s^{ - 1}}\)
4 \(5\,m/{s^{ - 1}}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365797 A block of mass \(m\) slides with velocity \(v\) along a frictionless level surface towards a block of mass \(4 m\) initially at rest. The velocity of centre of mass is

1 \(v / 5\)
2 \(v / 4\)
3 \(5 v / 2\)
4 \((4 / 5) v\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365798 Two objects of masses \(300\;g\) and \(700\;g\) posseses velocities \(15\hat i\;m{\rm{/}}s\) and \(4\hat i + 6\hat j\;m{\rm{/}}s\) respectively. The velocity of their centre of mass in \(m{\rm{/}}s\) is

1 \(7 \hat{i}+8 \hat{j}\)
2 \(7.3 \hat{i}+4.2 \hat{j}\)
3 \(5 \hat{i}+4 \hat{j}\)
4 \(2 \hat{i}+6 \hat{j}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365799 Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are \(v_{1}\) and \(v_{2}\) at any instant, then the speed of centre of mass of the system will be:

1 \(v_{1}+v_{2}\)
2 \(v_{1}-v_{2}\)
3 Zero
4 \(\dfrac{v_{1}+v_{2}}{2}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365800 Assertion :
The centre mass of an electron and proton, when released remains at rest.
Reason :
Proton is heavier than electron.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365796 A massless spring of force constant \(1000 {Nm}^{-1}\) is compressed a distance of 20 \(cm\) between discs of 8 \(kg\) and 2 \(kg\) , spring is not attached to discs. The system is given an initial velocity \(3 {~ms}^{-1}\) perpendicular to length of spring as shown in the figure. What is ground frame velocity of 2 \(kg\) block when spring regains its natural length.
supporting img

1 \(1\,m/{s^{ - 1}}\)
2 \(8\,m/{s^{ - 1}}\)
3 \(6\,m/{s^{ - 1}}\)
4 \(5\,m/{s^{ - 1}}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365797 A block of mass \(m\) slides with velocity \(v\) along a frictionless level surface towards a block of mass \(4 m\) initially at rest. The velocity of centre of mass is

1 \(v / 5\)
2 \(v / 4\)
3 \(5 v / 2\)
4 \((4 / 5) v\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365798 Two objects of masses \(300\;g\) and \(700\;g\) posseses velocities \(15\hat i\;m{\rm{/}}s\) and \(4\hat i + 6\hat j\;m{\rm{/}}s\) respectively. The velocity of their centre of mass in \(m{\rm{/}}s\) is

1 \(7 \hat{i}+8 \hat{j}\)
2 \(7.3 \hat{i}+4.2 \hat{j}\)
3 \(5 \hat{i}+4 \hat{j}\)
4 \(2 \hat{i}+6 \hat{j}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365799 Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are \(v_{1}\) and \(v_{2}\) at any instant, then the speed of centre of mass of the system will be:

1 \(v_{1}+v_{2}\)
2 \(v_{1}-v_{2}\)
3 Zero
4 \(\dfrac{v_{1}+v_{2}}{2}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365800 Assertion :
The centre mass of an electron and proton, when released remains at rest.
Reason :
Proton is heavier than electron.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365796 A massless spring of force constant \(1000 {Nm}^{-1}\) is compressed a distance of 20 \(cm\) between discs of 8 \(kg\) and 2 \(kg\) , spring is not attached to discs. The system is given an initial velocity \(3 {~ms}^{-1}\) perpendicular to length of spring as shown in the figure. What is ground frame velocity of 2 \(kg\) block when spring regains its natural length.
supporting img

1 \(1\,m/{s^{ - 1}}\)
2 \(8\,m/{s^{ - 1}}\)
3 \(6\,m/{s^{ - 1}}\)
4 \(5\,m/{s^{ - 1}}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365797 A block of mass \(m\) slides with velocity \(v\) along a frictionless level surface towards a block of mass \(4 m\) initially at rest. The velocity of centre of mass is

1 \(v / 5\)
2 \(v / 4\)
3 \(5 v / 2\)
4 \((4 / 5) v\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365798 Two objects of masses \(300\;g\) and \(700\;g\) posseses velocities \(15\hat i\;m{\rm{/}}s\) and \(4\hat i + 6\hat j\;m{\rm{/}}s\) respectively. The velocity of their centre of mass in \(m{\rm{/}}s\) is

1 \(7 \hat{i}+8 \hat{j}\)
2 \(7.3 \hat{i}+4.2 \hat{j}\)
3 \(5 \hat{i}+4 \hat{j}\)
4 \(2 \hat{i}+6 \hat{j}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365799 Two particles which are initially at rest, move towards each other under the action of their internal attraction. If their speeds are \(v_{1}\) and \(v_{2}\) at any instant, then the speed of centre of mass of the system will be:

1 \(v_{1}+v_{2}\)
2 \(v_{1}-v_{2}\)
3 Zero
4 \(\dfrac{v_{1}+v_{2}}{2}\)
PHXI07:SYSTEMS OF PARTICLES AND ROTATIONAL MOTION

365800 Assertion :
The centre mass of an electron and proton, when released remains at rest.
Reason :
Proton is heavier than electron.

1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but reason is correct.