Rotational motion

Centre of mass of a body

• lies always along the edge

• lies always inside the body

• lies always outside the body

• may lie within or outside the body

The velocity of centre of mass of the system remains constant, if the total external force acting on the system is

• minimum

• maximum

• unity

• zero

A child is standing on one end of a long trolley moving with a speed v on a smooth horizontal floor. If the child starts running towards the other end with a speed u, the centre of mass of the system will move with a speed

• zero

• u + v

• v - u

• v

A couple produces

• purely translational motion

• purely rotational motion

• Both translational and rotational motion

• no motion

Moment of couple is called

• Angular momentum

• force

• torque

• impulse

Analogue of mass in rotational motion is

• moment of inertia

• radius of gyration

• torque

• angular momentum

Moment of inertia of a body depends on

• mass of the body

• axis of rotation of the body

• shape and size of the body

• all of these

A flywheel rotating at 420 rpm slows down at a constant rate of 2 rad/s. The time required to stop the flywheel is

• 22 s

• 11 s

• 44 s

• 12 s

A person is standing on a rotating table with metal sphere in his hands. If he withdraws his hands to the chest, then the effect on his angular velocity will be

• increases

• decreases

• remain same

• first increases then decreases

When a torque acting upon a system is zero. Which of the following will be constant?

• Force

• Linear impulse

• Linear momentum

• Angular momentum

Tags

NGSS.HS-PS2-2