have a surface contact when in motion

have a line or point contact when in motion

are kept in contact by the action of external forces, when in motion

are not held together mechanically

whole of the mechanism in the Ackerman steering gear is on the back of the front wheels

the Ackerman steering gear consists of turning pairs

the Ackerman steering gear is most economical

whole of the mechanism in the Ackerman steering gear is on the back of the front wheels and the Ackerman steering gear consists of turning pairs

lies

does not lie

zero

none of these

Right

Wrong

the centre of the disc

the point of contact

an infinite distance on the plane surface

the point on the circumference situated vertically opposite to the contact point