Here we learn the concepts of:

1. Rest – A body is said to be in a  state of rest when does not change its position with respect to the immediate surroundings
   Eg – A resting man, A tree in a park
2. Motion – A body is said to be in motion when it changes its position with respect to its immediate suroundings.
   Eg – A moving car
3. Rectilinear motion – a linear motion in which the direction of the velocity remains constant and the path is a straight line.
   In this case the motion does not necessarily have to be in a mathematically straight line; it means that the motion is non-circular,  non – oscillatory and can be defined in one dimension.
   Eg – A car moving on the highway at a steady velocity