Rotational Dynamics

The moments of inertia of two rotating bodies A and B about the same axis are I_A & I_B ( I_A > I_B ) and their angular momentum are equal. If K_A & K_B are their rotational kinetic energies then......

• K_A > K_B

• K_A < K_B

• K_A = K_B

• K_A = K_B = 0

A rigid body is rotating about an axis. to stop the rotation, we have to apply........

• pressure

• force

• momentum

• torque

Two rings have their moments of inertia in the ratio 2 : 1 and their diameters are in the ratio 2 : 1. The ratio of their masses will be..........

• 2 : 1

• 1 : 2

• 1 : 4

• 1 : 1

A 2 kg mass is rotating on a circular path of radius 0.8 m with angular velocity of 44 rad/s. If the radius of the path becomes 1m, then the angular velocity will be ........

• 8.12 rad/s

• 19.28 rad/s

• 28.16 rad/s

• 35.26 rad/s

A disc of mass 2 kg and radius 20 cm is free rotate about an axis through its centre and perpendicular to the disc. If a force of 50 N is applied tangentially to the disc, then the angular acceleration is.......

• 250 rad/s²

• 25 rad/s²

• 2.5 rad/s²

• 0.25 rad/s²

Tags

NGSS.HS-PS2-1

For the uniform circular motion of a body, the direction of the centripetal force of a body.........

• depends on the mass of the body

• depends on the linear speed of the body

• depends on the sense of rotation(clockwise or anticlockwise) of the body

• does not depend on the sense of rotation(clockwise or anticlockwise) of the body

A car is moving on a banked track of radius 10m with a constant speed of 10 m/s. The angle of banking is ........

(g = 10 m/s²)

• 90⁰

• 60⁰

• 45⁰

• 30⁰

Tags

NGSS.HS-PS2-4

A cyclist moving at a speed of 20 m/s takes a turn. If he doubles his speed, then the chance of overturn........

• is halved

• is doubled

• becomes 4 times

• becomes 1/4 times

A coin is placed on a disc rotating at a speed of 45 rpm. It flies away when the rotational speed of the disc becomes 50 rpm. If another identical coin is placed on the first coin , then both of them will fly away when the rotational speed is.......

• 12.5 rpm

• 25 rpm

• 50 rpm

• 100 rpm

A stone of mass 16 kg is attached to a string 144 m long and is whirled in a horizontal circle. The maximum tension the string can withstand is 16 N. Then the maximum speed that can be given to the stone without breaking the string is.........

• 12 m/s

• 14 m/s

• 16 m/s

• 20 m/s