State and explain uniform and non-uniform motions.

The velocity of a body is said to be uniform when it covers equal distances in equal intervals of time however small the intervals may be, the direction remaining constant.
The velocity of a body is said to be non-uniform when it passes over unequal distances in successive equal intervals of time or changes its direction of motion.
For example, a train has a uniform velocity of 6m per second if it regularly moves a distance of 6m in one second in a constant direction. If the train does not regularly traverse a distance of 6m in a second, but instead halts at station, then its velocity at the time of leaving a station or reaching it will be different from its velocity between the station and so we state that it has non-uniform velocity.