Centre of Mass and Its Motion

IMPORTANT

Centre of Mass and Its Motion: Overview

This topic covers concepts such as Centre of Mass, Centre of Mass of Two Particles, Centre of Mass of More than Two Particles, Centre of Mass of Symmetrical Bodies, Centre of Mass of Continuous Bodies, Velocity of Centre of Mass, etc.

Important Questions on Centre of Mass and Its Motion

MEDIUM
IMPORTANT

Two spherical bodies of mass M and 5M and radii R and 2R respectively are released in free space with initial separation between their centres equal to 12R. If they attract each other due to gravitational force only, then the distance covered by the smaller body just before collision is–

EASY
IMPORTANT

If the resultant of all the external forces acting on a body be zero, the centre of mass of the system

EASY
IMPORTANT

Two bodies of different masses 2 kg and 4 kg are moving with velocities 2 m s-1 and 1 m s-1 towards each other due to mutual gravitational attraction. Then the velocity of the centre of mass is

EASY
IMPORTANT

If the separation between carbon and oxygen in CO molecule is 0.12 nm, then the distance of the center of mass from the carbon atom is

HARD
IMPORTANT

A block of mass m is projected towards a wedge of mass M with a velocity u as shown in the figure below. All the surfaces are smooth. Find the expression for the maximum height attained by the block as it moves on the surface of the wedge.

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MEDIUM
IMPORTANT

Two masses at a distance equal to D are moving towards each other due to gravitational pull as shown in the figure below. Find the expression for the relative velocity of two masses when the distance between the two masses become D/2.

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MEDIUM
IMPORTANT

The concept of reduced mass can be used in the problems where the force between the two masses is:

HARD
IMPORTANT

Two masses m and 2m are connected by a spring are kept on a frictionless table as shown in the figure below. The block of mass m is imparted the velocity equal to v towards right. Find the maximum compression in the spring.

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MEDIUM
IMPORTANT

What do you understand by reduced mass?

HARD
IMPORTANT

A uniform thin wooden plank AB of length L and mass M is kept on a table with its B end slightly outside the edge of the table. When an impulse J is given to the end B, the plank moves up with centre of mass rising a distance h from the surface of the table. Then,

MEDIUM
IMPORTANT

A small ring is rolling without slipping on the circumference of a large bowl as shown below in the figure. The ring is moving down at P1, comes down to the lower most point P2 and is climbing up at P3. Let vCM denote the velocity of the centre of mass of the ring. Choose the correct statement regarding the frictional force on the ring.

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EASY
IMPORTANT

The distance between the carbon atom and the oxygen atom in a carbon monoxide molecule is 1.1 A. Given, mass of carbon atom is 12 a.m. u and mass of oxygen atom is 16 a.m.u. Calculate the position of the centre of mass of the carbon monoxide molecule.

EASY
IMPORTANT

A tank with uniform cross-sectional area A is filled with a liquid of density ρ upto a height h. What is the potential energy stored in the system ?  (where g denotes the acceleration due to gravity)

MEDIUM
IMPORTANT

The distance of the centre of mass of the T-shaped plate from O is,

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EASY
IMPORTANT

Two particles of equal mass have velocities v1=2i^ m s-1 and v2=2j^ m s-1. First particle has an acceleration a1=(3i^+3j^) m s-2 while the acceleration of the other particle is zero. The centre of mass of the two particles moves in a path of

HARD
IMPORTANT

A man of mass M stands at one end of a plank of length L which lies at rest on a frictionless surface. The man walks to the other end of the plank. If the mass of plank is M3, the distance that the Man moves relative to the ground is:

EASY
IMPORTANT

A circular hole of radius 1 cm is cut off from a disc of radius 6 cm. The centre of the hole is 3 cm from the centre of the disc. Then the distance of the centre of mass of the remaining disc from the centre of the disc is

EASY
IMPORTANT

For a bangle, the centre of mass lie outside the body.

EASY
IMPORTANT

The center of mass of a system of particles does not depend upon force acting on particle.

HARD
IMPORTANT

Two particles A and B initially at rest, move towards each other, under mutual force of attraction. At an instance when the speed of A is v and speed of B is 2v, the centre of mass (CM) remains at rest. This statement is _____. Choose from (True/False).