what is the difference between linear and rotational motion???

Linear motion is a motion of a particle along a straight line.

Example. The motion of the particle between A and B shown below is an example of linear motion.

Rotational Motion is a type of motion in which a body and every constituent particle spins about an axis (rotational axis) such that they trace concentric circles about the axis. The angular speeds of particles would differ in this case. Example: Rotation of Earth.