Centre of Mass and Collision

The adjacent hoop has a diameter of 1 meter, what are the coordinates of its centre of mass

• 1,1
• 0.5,1
• 0.5,0.5
• 1,0.5

Two unequal masses are tied together with a compressed spring. When the cord is burnt with a matchstick releasing the spring; the two masses fly apart with equal :

• Momentum

• Acceleration

• Speed

• Kinetic energy

Choose the correct statement.

(A) The position of centre of mass of a system is dependent on the choice of co-ordinate system.

(B) Newton's second law of motion is applicable to the centre of mass of the system.

(C) When no external force acts on a body, the acceleration of centre of mass is zero.

(D) Internal forces can change the state of centre of mass.

• Both A and B are correct

• Both B and C are wrong

• Both A and C are wrong

• Both A and D are wrong

If all the particles of a system lie in X-Y plane, is it necessary that the centre of mass be in X-Y plane?

• Yes

• No

Two balls are thrown simultaneously in air. The acceleration of the centre of mass of the two balls while in air:

• depends on the direction of the motion of the balls

• depends on the masses of the two balls

• depends on the speeds of the two balls

• is equal to g

• 1

• 2

• 3

• 4

• 1

• 2

• 3

• 4

• 1

• 2

• 3

• 4

• 1

• 2

• 3

• 4

During an explosion, momentum is _____ conserved.

• always

• sometimes

• never