Sometimes when the speed of a vehicle is increased,its body starts to bounce. Why?

What is resonance? Give its example.

The amplitude of a simple pendulum,oscillating in air with a small spherical bob,decreases from $10 \ cm$ to $8 \ cm$ in $40 \ s$. Assuming that Stokes' law is valid,and the ratio of the coefficient of viscosity of air to that of carbon dioxide is $1.3$. The time in which the amplitude of this pendulum will reduce from $10 \ cm$ to $5 \ cm$ in carbon dioxide will be close to ..... $s$ $(\ln 5 = 1.601, \ln 2 = 0.693)$

Explain the behaviour of the oscillator when the driving frequency is far from the natural frequency in small damped oscillations.

What are damped oscillations? Discuss them using the illustration of a spring.

In forced oscillations,a particle oscillates simple harmonically with a frequency equal to