Quiz 4 Ch 2 & 3

In a forced vibration with viscous damping, maximum amplitude occurs when forced frequency is

• Equal to natural frequency

• Slightly less than natural frequency

• Slightly greater than natural frequency

• Zero

If air resistance is neglected, while it is executing small oscillations the acceleration of the bob of a simple pendulum at the mid-point of its swing will be

• zero

• a minimum but not equal to zero

• a maximum

• not determinable unless the length of the pendulum and the mass of the bob are known

• equal to one

• less than one

For a harmonically excited single degree of freedom viscous damped system, which one of the following is correct?

• Inertia force leads damping force by 90° while damping force leads spring force by 90°

• Spring force leads damping force by 90° while damping force leads inertia force by 180°

• Spring force and damping force are in phase, and inertia force leads them by 90°

• Spring force and inertia force are in phase, and damping force leads them by 90°

In a system subjected to damped forced vibrations, the ratio of maximum displacement to the static deflection is known as

• Critical damping ratio

• Damping factor

• Logarithmic decrement

• Magnification factor