NEET Physics Centre of Mass Centre of Gravity and Principle of Moments Online Test Set A

1. The position of centre of mass of a system of particles does not depend upon the.

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3. Two objects P and Q initially at rest move towards each other under mutual force of attraction. At the instant when the velocity of P is v and that of Q is 2v, the velocity of centre of mass of the system is

4. The centre of mass of three bodies each of mass 1 kg located at the points (0, 0), (3, 0) and (0, 4) in the XY plane is

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7. Two bodies of masses 2 kg and 4 kg are moving with velocities 2 m/s and 10 m/s respectively along same direction. Then the velocity of their centre of mass will be

8. A system consists of three particles, each of mass m and located at (1, 1), (2, 2) and (3, 3). The co-ordinates of the centre of mass are

9. Statement 1 : When you lean behind over the hind legs of the chair, the chair falls back after a certain angle.
Statement 2 : Centre of mass lying outside the system makes the system unstable.

10. A man stands at one end of a boat which is stationary in water. Neglect water resistance. The man now moves to the other end of the boat and again becomes stationary. The centre of mass of the ‘man plus boat’ system will remain stationary with respect to water

11. A shell following a parabolic path explodes somewhere in its flight. The centre of mass of fragments will continue to move in

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13. Assertion : The centre of mass of an isolated system has a constant velocity.
Reason : If centre of mass of an isolated system is already at rest, it remains at rest.

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15. Three masses are placed on the x-axis : 300 g at origin, 500 g at x = 40 cm and 400 g at x = 70 cm. The distance of the centre of mass from the origin is

16. Consider a system of two particles having masses m₁ and m₂ . If the particle of mass m1 is pushed towards the centre of mass particles through a distance d, by what distance would the particle of mass m₂ move so as to keep the mass centre of particles at the original position?

17. Assertion : The centre of mass of a two particle system lies on the line joining the two particle, being closer to the heavier particle.
Reason : Product of mass of particle and its distance from centre of mass is numerically equal to product of mass of other particle and its distance from centre of mass.

18. The motion of binary stars , S₁ and S₂ is the combination of ....X.... and ....Y.... . Here, X and Y refer to

19. A stick is thrown in the air and lands on the ground at some distance from the thrower. The centre of mass of the stick will move along a parabolic path

20. There are some passengers inside a stationary railway compartment. The centre of mass of the compartment itself (without the passengers) is C₁, while the centre of mass of the ‘compartment plus passengers’ system is C₂. If the passengers move about inside the compartment then

21. Consider the following statements and choose the correct option.
I. Position vector of centre of mass of two particles of equal mass is equal to the position vector of either particle.
II. Centre of mass is always at the mid-point of the line joining two particles
III. Centre of mass of a body can lie where there is no mass

22. Centre of mass of the earth and the moon system lies

23. In rotation of a rigid body about a fixed axis, every ...A...of the body moves in a ...B..., which lies in a plane ...C... to the axis and has its centre on the axis. Here, A, B and C refer to

24. If the resultant of all external forces is zero, then velocity of centre of mass will be

25. The motion of a rigid body which is not pivoted or fixed in some way is either a pure ...A... or a combination of translation and rotation. The motion of a rigid body which is pivoted or fixed in some way is ...B... Here, A and B refer to

26. Two spheres A and B of masses m and 2m and radii 2R and R respectively are placed in contact as shown. The COM of the system lies

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28. In rotatory motion, linear velocities of all the particles of the body are

29. A pulley fixed to the ceiling carries a string with blocks of mass m and 3 m attached to its ends. The masses of string and pulley are negligible. When the system is released, its centre of mass moves with what acceleration ?

30. The centre of mass of two particles lies on the line

31. The motion of the centre of mass depends on

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33. The position of centre of mass of a system of particles does not depend upon the

34. Position vector of centre of mass of two particles system is given by

35. The centre of mass of a body