A planetary gear train has four gears and one carrier. Angular velocities of the gears are $${\omega _1},{\omega _2},{\omega _3},$$ and $${\omega _4}$$ respectively. The carrier rotates with angular velocity $${\omega _5}.$$

For $${{\omega _1} = 60}$$ rpm clockwise $$(CW)$$ when looked from the left, what is the angular velocity of the carrier and its direction so that Gear $$4$$ rotates in counter clockwise $$(CCW)$$ direction at twice the angular velocity of Gear $$1$$ when looked from the left?

A planetary gear train has four gears and one carrier. Angular velocities of the gears are $${\omega _1},{\omega _2},{\omega _3},$$ and $${\omega _4}$$ respectively. The carrier rotates with angular velocity $${\omega _5}.$$

What is the relation between the angular velocities of Gear $$1$$ and Gear $$4$$?

Match the items in columns $$I$$ and $$II$$

Column $$I$$
$$P.$$ Addendum
$$Q.$$ Instantaneous center of velocity
$$R.$$ Section modulus
$$S.$$ Prince circle

Column $$II$$
$$1.$$ Cam
$$2.$$ Beam
$$3.$$ Linkage
$$4.$$ Gear

The overall gear ratio in a 2 stage speed reduction gear box (with all spur gears) is 12. The input and output shafts of the gear box are collinear. The countershafts which is parallel to the input and output shafts has a gear (Z₂ teeth) and pinion (Z₃ = 15 teeth) to mesh with pinion (Z₁ = 16 teeth) on the input shafts and gear (Z₄ teeth) on the output shafts respectively. It was decided to use a gear ratio of 4 with 3 module in the first stage and 4 module in the second stage.

The centre distance in the second stage is