Pendulum comes from the Latin word pendulus meaning “hanging down.” A simple pendulum consists of a bob suspended at the end of a string or wire so light, it is considered massless. The bob is suspended from a pivot and moves back and forth with constant amplitude. This happens in ideal cases only, where there is no friction.
Oscillatory motion of a simple pendulum
Oscillatory motion is defined as the to and fro motion of the pendulum in a periodic fashion, and the centre point of oscillation is known as the equilibrium position.
Amplitude of a simple pendulum
Amplitude is defined as the distance traveled by the pendulum from the equilibrium position to one side.
Period of a simple pendulum
The period of a simple pendulum is influenced by:
- Length of the pendulum
It is directly proportional to the length (distance between the point of suspension to the centre of the bob) of the pendulum; when the length increases, its period also increases.
- Position of the pendulum in relation to Earth
The strength of Earth’s gravitational field is not uniform everywhere. At low altitudes and Earth’s poles, a given pendulum swings faster and has a shorter period. On the other hand, at high altitudes and the Equator, it swings slower and has a longer period.
The period of the pendulum is independent of the mass of the bob and is given by,
T = 2π √L/g
Where L is the length of the string and g is the acceleration due to gravity.
References:
- Milham, Willis I. (1945). Time and Timekeepers. MacMillan., p.188-194