A thin walled spherical shell is subjected to an internal pressure. If the radius of the shell is increased by 1% and the thickness is reduced by 1%, with the internal pressure remaining the same, the percentage change in the circumferential (hoop) stress is

A solid disc of radius $$r$$ rolls without slipping on a horizontal floor with angular velocity $$\omega $$ and angular acceleration $$\alpha $$. The magnitude of the acceleration of the point of contact on the disc is

In the mechanism given below, if the angular velocity of the eccentric circular disc is $$1$$ rad/s, the angular velocity (rad/s) of the follower link for the instant shown in the figure is

Note : $$All$$ $$dimensions$$ $$are$$ $$in$$ $$mm$$

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