Theory of Machine
To obviate axial thrust, following gear drive is used

Double helical gears having opposite teeth
Single helical gear in which one of the teeth of helix angle a is more
Double helical gears having identical teeth
Mutter gears

ANSWER DOWNLOAD EXAMIANS APP

Theory of Machine
In elliptical trammels

One pair turning and three pairs sliding
All four pairs are turning
Three pairs turning and one pair sliding
Two pairs turning and two pairs sliding

ANSWER DOWNLOAD EXAMIANS APP