MOTIONS IN ONE, TWO AND THREE DIMENSIONS (TYPE OF MOTION)

As position of the object may change with time due to change in one or two or all the three coordinates, so we have classified motion as follows:

MOTION IN ONE DIMENSION:

If only one of the three co-ordinates specifying the position of object changes w.r.t. time. In such a case the object moves along a straight line and the motion therefore is also known as rectilinear or linear motion.

Ex.  

• Motion of train along straight railway track.
• An object falling freely under gravity.
• When a particle moves from P1 to P2 along a straight line path only the x-co-ordinate changes.

MOTION IN TWO DIMENSION:

If two of the three co-ordinates specifying the position of object changes w.r.t. time, then the motion of object is called two dimensional. In such a motion the object moves in a plane.

Ex.   

• Motion of queen on carom board.
•  An insect crawling on the floor of the room.
• Motion of object in horizontal and vertical circles etc.
• Motion of planets around the sun.
• A car moving along a zigzag path on a level road.

MOTION IS THREE DIMENSION:

If all the three co-ordinates specifying the position of object changes w.r.t. time, then the motion of object is called 3-D. In such a motion the object moves in a space.

Ex.   

• A bird flying in the sky (also kite).
• Random motion of gas molecules.
• Motion of an aeroplane in space.