1391. If the distance between two mass particles is doubled, the gravitational force between them :

A. Is reduced to half of the original value
B. Is reduced to one fourth of the original value *
C. Becomes double
D. Becomes four times

1392. Angular displacement generally expressed in :

A. Degrees
B. Revolution
C. Radian
D. All of these 

1393. Radian is the unit of angular displacement which is :

A. Less than degree
B. Greater than degree *
C. Equal
D. None of these

1394. A couple produces :

A. Purely linear motion
B. Purely rotational motion *
C. Linear and rotational motion
D. No Motion

1395. The rate at which the angular displacement is changing with time is called :

A. Angular acceleration
B. Angular Velocity *
C. Average angular velocity
D. None of these

1396. S.I unit of angular velocity is :

A. Radian per second *
B. Revolution per minute
C. Degree per second
D. None of thes e

1397. Angular acceleration is a :

A. Scalar quantity
B. Variable quantity
C. Vecor quantity *
D. None of these

1398. The units of angular acceleration is :

A. Radian
B. Radian per second
C. Radian persecond2 *
D. None of these

1399. THe axis of ration of an object will not change its orientation unless :

A. Internal torque acts
B. Internal torque acts in one direction
C. External torque acts *
D. None of these

1400. The linear velocity in a circle is called :

A. Linear velocity
B. Angular velocity
C. Tangential velocity 
D. None of these