DEFINITIONS: MECHANICS 5

1. Angular Velocity
   Angular velocity is the rate of change of angle with respect to time.
   The unit of angular velocity is the radian per second (rad s^-1)
   
   
2. Centripetal Force
   If a body is moving in a circle the force towards the centre needed to keep it moving is called centripetal force.
   
   
3. Centripetal Acceleration
   If a body is moving in a circle the acceleration towards the centre of the circle is called centripetal acceleration.
   
   
4. Period of an Orbit
   The time taken for a satellite to go once around the central body
   is called the periodic time or simply the period (T) of the orbit.
   
   
5. Hooke's Law
   When an object is bent, stretched or compressed by a displacement s,
   the restoring force F is directly proportional to the displacement,
   provided the elastic limit is not exceeded.
   
   
6. Simple Harmonic Motion
   A body is said to be moving with simple harmonic motion if:
   (i) its acceleration is directly proportional to its distance from a fixed point of its path and
   (ii) its acceleration is always directed towards that point.