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The centre of mass of a body lies always

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Important Questions on Motion of System of Particles and Rigid Body

MEDIUM
A rod of length L has non-uniform linear mass density given by ρx=a+bxL2, where a and b are constants and 0xL . The value of x for the centre of mass of the rod is at:
MEDIUM

A uniform rectangular thin sheet ABCD of mass M has length a and breadth b, as shown in the figure. If the shaded portion HBGO is cut-off, the coordinates of the centre of mass of the remaining portion will be:


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HARD

As shown in figure, when a spherical cavity (centred at O ) of radius 1 is cut out of a uniform sphere of radius R (centred at C ), the centre of mass of remaining (shaded part of sphere is at G, i.e., on the surface of the cavity. R can be determined by the equation:
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MEDIUM

Three identical spheres, each of mass M, are placed at the corners of a right angle triangle with mutually perpendicular sides equal to 2 m (see figure). Taking the point of intersection of the two mutually perpendicular sides as the origin, find the position vector of centre of mass.

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EASY
Two spherical bodies of mass M and 5M and radii R and 2R 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 before collision is:
MEDIUM
Two particles of mass 5 kg and 10 kg respectively are attached to the two ends of a rigid rod of length 1 m with negligible mass. The centre of mass of the system from the 5 kg particle is nearly at a distance of:
HARD
The coordinates of the centre of mass of a uniform flag-shaped lamina (thin flat plate) of mass 4 kg. (The coordinates of the same are shown in the figure) are:

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MEDIUM
A uniform wire of length L' with centre of mass at the origin is lying along the x- axis. The wire is bent in the form of a circle such that its lowest point is at the origin. Then the shift of centre of mass is
MEDIUM
Which of the following statements are correct?

(i) Centre of mass of a body always coincides with the centre of gravity of the body.

(ii) Centre of mass of a body is the point at which the total gravitational torque on the body is zero

(iii) A couple on a body produce both translational and rotational motion in a body.

(iv) Mechanical advantage greater than one means that small effort can be used to lift a large load.
HARD

In the figure shown ABC is a uniform wire. If the center of mass of the wire lies vertically below point A, then BCAB is close to

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EASY
The center of mass on combining two masses m and M(M>m) will be
MEDIUM
The position vector of the center of mass rcm  of an asymmetric uniform bar of negligible area of cross-section as shown in figure is:

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MEDIUM

Three point particles of masses 1.0 kg, 1.5 kg and 2.5 kg are placed at three corners of a right angle triangle of sides 4.0 cm, 3.0 cm and 5.0 cm as shown in the figure. The centre of mass of the system is at a point:
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MEDIUM
A ball of mass 100 g is dropped at time t=0. A second ball of mass 200 g is dropped from the same point at t=0.2 s. The distance between the center of mass of two balls and the release point at t=0.4 s is: (Assume g=10 m s-2)
EASY
The centre of mass of a system of two bodies of masses M and m, (M>m), separated by a distance d is:
EASY

Figure shows a rectangular copper plate with its centre of mass at the origin O and side AB=2BC=2 m. If a quarter part of the plate (shown as shaded) is removed, the centre of mass of the remaining plate would lie at

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EASY

Three particles of masses 50 g, 100 g and 150 g are placed at the vertices of an equilateral triangle of side 1 m (as shown in the figure). The x,y coordinates of the centre of mass will be:
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MEDIUM
A uniform thin rod AB of length L has linear mass density μx=a+bxL, where x is measured from A. If the CM of the rod lies at a distance of 712L from A, then a and b are related as:
HARD
Distance of the centre of mass of a solid uniform cone from its vertex is z0. If the radius of its base is R and its height is h then z0 is equal to: