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प्रश्न
You are waiting for a train on a railway platform. Your three-year-old niece is standing on your iron trunk containing the luggage. Why does the trunk not recoil as she jumps off on the platform?
उत्तर
The trunk does not recoil as the girl jumps off on the platform because the force exerted by the girl is less than the limiting friction between the platform and the iron trunk.
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संबंधित प्रश्न
Consider the following two statements:
(A) Linear momentum of the system remains constant.
(B) Centre of mass of the system remains at rest.
A nonzero external force acts on a system of particles. The velocity and the acceleration of the centre of mass are found to be v0 and a0 at instant t. It is possible that
(a) v0 = 0, a0 = 0
(b) v0 = 0, a0 ≠ 0
(c) v0 ≠ 0, a0 = 0
(d) v0 ≠ 0, a0 ≠ 0
Find the centre of mass of a uniform plate having semicircular inner and outer boundaries of radii R1 and R2.
Find the ratio of the linear momenta of two particles of masses 1.0 kg and 4.0 kg if their kinetic energies are equal.
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(a) the linear speeds of the balls A and B after the collision, (b) the velocity of the centre of mass C of the system A + B + P and (c) the angular speed of the system about C after the collision.
[Hint : The light rod will exert a force on the ball B
only along its length.]
Solve the following problem.
A uniform solid sphere of radius R has a hole of radius R/2 drilled inside it. One end of the hole is at the center of the sphere while the other is at the boundary. Locate center of mass of the remaining sphere.
A round object of mass M and radius R rolls down without slipping along an inclined plane. The frictional force, ______
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A mass of 1kg is suspended by a string. It is first lifted up with an acceleration of 4.9 m/s2 and then lowered down with same acceleration. The ratio of tensions in the string in the two cases, respectively is g = 9.8 m/s2 ______.
Which of the following statements are correct?
A uniform square plate has a small piece Q of an irregular shape removed and glued to the centre of the plate leaving a hole behind figure. The CM of the plate is now in the following quadrant of x-y plane ______.
Find the centre of mass of a uniform (a) half-disc, (b) quarter-disc.
The mass per unit length of a non-uniform rod of length L varies as m = λx where λ is constant. The centre of mass of the rod will be at ______.
A point charge Q is situated at point B on the ground. A point charge q of mass m is vertically dropped along line AB from a multi-storey building of height h. Find the position of the point charge q when it is in equilibrium.
