**NEET Physics Notes Oscillations-Terms Related to SHM**

**Terms Related to SHM**

The few important terms related to simple harmonic motion are given as

**Displacement**

The displacement of a particle executing SHM is, in general, expressed as

where, A is the amplitude of SHM

ω the angular frequency

Φ is the initial phase of SHM.

However, displacement may also be expressed as

**Velocity**

The velocity of a particle executing SHM at an instant is defined as the time rate of change of its displacement at that instant. Velocity,

At the mean position (y = 0), during its motion and at the extreme positions

**Acceleration**

The acceleration of a particle executing SHM at an instant is defined as the time rate of change of velocity at that instant. Acceleration,

The acceleration is also a variable. At the mean position (y = 0), acceleration a = 0 and at the extreme position (y = ± A), the acceleration is

**Phase and It’s Relationship**

Phase is that physical quantity which tells about the position and direction of motion of any particle at any moment. It is denoted by Φ In SHM, the velocity

is ahead of the displacement by a phase \frac{\pi}{2} and the acceleration is further ahead of the velocity by a phase of \frac{\pi}{2}

**Time Period**

The time taken by a particle to complete one oscillation is called time period. It is denoted by T.

**Oscillations of a Spring**

A spring pendulum consists of a point (small sized) mass m either suspended from a massless (or light) spring or placed on a smooth horizontal plane attached with a spring.

If the mass is once pulled, so as to stretch the spring and is then released, then a restoring force acts on it which continuously tries to restore its mean position, restoring force F = – kl, where k is force constant and 1 is the change in length of the spring under the restoring force the spring pendulum oscillates simple harmonically having time period and frequency given by

If the spring is not light but has a mass m_{s}, then

If two masses m_{1} and m_{2}, connected by a spring, are made to oscillate on a horizontal surface, then its