Centre of Mass

IMPORTANT

Centre of Mass: Overview

This Topic covers sub-topics such as Linear Momentum of System of Particles, Direction of Movement of Center of Mass, Centre of Mass and Centre of Mass Frame, Centre of Mass of Symmetrical Bodies and, Conservation of Linear Momentum of System of Particles

Important Questions on Centre of Mass

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

Distance of centre of mass of a thin uniform semi-circular disc of radius R from its centre is

EASY
IMPORTANT

Mass is distributed uniformly over a thin triangular plate and positions of two vertices are given by (1, 3) and (2, -4). What is the position of 3rd vertex if the centre of mass of the plate lies at the centre of origin?

EASY
IMPORTANT

The ball is released from rest. Find centre of mass of large sphere when small sphere reaches the extreme position. 

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MEDIUM
IMPORTANT

 List the conditions to increase the stability of a body.

HARD
IMPORTANT

Why is it important to find the centre of mass of a body?

HARD
IMPORTANT

Draw a diagram and explain how to find centre of mass of an irregularly shaped lamina.

EASY
IMPORTANT

A small sphere of radius slides on a smooth circular part of radius R on a wedge of mass M. The Displacement of sphere when it slides to bottom most position

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EASY
IMPORTANT

The density of a linear rod of length L varies as λ=λ0xL x is the distance from the left end of rod. Location of centre of mass of the rod, is

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EASY
IMPORTANT

Locate centre of mass of a system of three particles, as shown in the figure.

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EASY
IMPORTANT

The velocity of the centre of mass of a solid sphere of radius R rotating with angular velocity about an axis passing through its centre of mass is

EASY
IMPORTANT

What is the distance of centre of mass from 4 kg mass in the following arrangement:

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EASY
IMPORTANT

The particles of mass 1 kg, 2 kg and 3 kg are placed at the vertices of an equilateral triangle of side 1 m as shown in the figure. The co-ordinates of centre of mass will be

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EASY
IMPORTANT

Four particles having masses 2 kg, 3 kg4 kg and 6 kg are placed at four vertices A, B, C and D respectively of square of side 1 m as shown in the figure. The position of centre of mass of the system of particles is

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EASY
IMPORTANT

Two particles of masses, 2 kg and 4 kg, are projected from the top of a tower simultaneously, such that 2 kg of mass is projected with a speed 20 m s-1 at an angle 30 above horizontal and 4 kg is projected at 40 m s-1 horizontally. The acceleration of the centre of mass of the system of two particles will be:
 

EASY
IMPORTANT

Two balls with masses m1=3 kg and m2=5 kg have initial velocities v1=v2 = 5 m s-1 in the directions as shown in the figure. They collide at the origin.
(a) Find the velocity of the centre of mass 3 s before the collision.

(b) Find the position of the centre of mass 2 s after the collision.

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EASY
IMPORTANT

Find the velocity of centre of mass if the triangle formed is equilateral.

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MEDIUM
IMPORTANT

The centre of a disc rolling without slipping on a plane surface moves with speed u. A particle, on the lower half of the rim making an angle 60° with vertical, will be moving at speed 

MEDIUM
IMPORTANT

In case of pure rolling, what will be the velocity of point A of the ring of radius R ?

 

MEDIUM
IMPORTANT

Linear mass density of rod of length l is directly proportional to  x3, where x is distance from one end of rod. Centre of mass of rod lies at a distance