Which one of the following is used to convert a rotational motion into a translational motion?

The following are the data for two crossed helical gears used for speed reduction:
Gear $$I:$$ Pitch circle diameter in the plane of rotation 80mm and helix angle 30^o

Gear $$II:$$ Pitch circle diameter in the plane of rotation 120mm and helix angle 22.5^o

If the input speed is 1440 rpm. The output speed in rpm is

Tooth interference in an external involute spur gear pair can be reduced by

A 1.5 kW motor is running at 1440 rev/min. Its is to be connected to a stirrer running at 36 rev/min. The gearing arrangement suitable for this application is