## Theory of Machine Critical damping is a function of

Mass and damping coefficient
Mass and natural frequency
Damping coefficient and natural frequency
Mass and stiffness

## Theory of Machine In a flat collar pivot bearing, the moment due to friction is proportional to

(r₁³ - r₂³)/(r₁ - r₂)
(r₁³ - r₂³)/(r₁² - r₂²)
(r₁² - r₂²)/(r₁ + r₂)
(r₁² - r₂²)/(r₁ - r₂)

Oscillating
All of these
Reciprocating
Rotating

## Theory of Machine The static balancing is satisfactory for low speed rotors but with increasing speeds, dynamic balancing becomes necessary. This is because, the

Unbalanced couples are caused only at higher speeds
Unbalanced forces are not dangerous at higher speeds
Effects of unbalances are proportional to the square of the speed
Effects of unbalances are directly proportional to the speed

## Theory of Machine When two pulleys of different diameters are connected by means of an open belt, the angle of contact at the ________ pulley must be taken into consideration.

None of the listed here
Smaller OR Larger
Smaller
Larger