Quantrex Quantrex AcademyJEE · NEET · NDA PYQs with solutions Open app
NEET2017PhysicsCenter of Mass, Momentum and CollisionActual

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

Options

  1. A(ii) and (iv)
  2. B(i) and (ii)
  3. C(ii) and (iii)
  4. D(iii) and (iv)

Correct answer

A. (ii) and (iv)

Step-by-step solution

(i) Centre of gravity coincides with centre of mass for bodies when gravitational field is uniform (usually for bodies of small height). (ii) Since the gravitational force can be assumed to be centred at the centre of gravity, so torque of gravitational force about the centre of gravity must be zero. In mechanics, usually we deal with the objects of small height for which torque of gravitational force about centre of mass will also be zero. (iii) Couple produces only rotational motion. (iv) Mechanical advantage = L

Practice Center of Mass, Momentum and Collision on Quantrex Academy →

More from Center of Mass, Momentum and Collision

A frictionless circular wire of unit radius is fixed on the horizontal plane. Two point particles of unit mass start moving simultaneously from point A ( = 2 ) with identical unifo 2026Bob B of mass m at rest is hanging vertically from the ceiling via a massless string of length 10 m, as shown in the figure. Point mass A of mass m travelling horizontally with spe 2026A ball of mass 0.5 kg is dropped from a height of 40 m . The ball hits the ground and rises to a height of 10 m . The impulse imparted to the ball during its collision with the gro 2025Two bodies A and B of same mass undergo completely inelastic one dimensional collision. The body A moves with velocity v₁ while body B is at rest before collision. The velocity of 2024Two 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 3 v , the speed of cent 2023A 1 ~kg object strikes a wall with velocity 1 ~ms ⁻¹ at an angle of 60^ with the wall and reflects at the same angle. If it remains in contact with wall for 0.1 ~s , then the force 2023A bullet of mass m hits a block of mass M elastically. The transfer of energy is the maximum, when 2023A shell of mass m is at rest initially. It explodes into three fragments having mass in the ratio 2 : 2 : 1 . If the fragments having equal mass fly off along mutually perpendicula 2022 Full Center of Mass, Momentum and Collision list All NEET PYQs