- If a body stays at the same position with time, it is at rest.

- If the body changes its position with time, it is in motion.

- Motion is said to be rectilinear if the body moves in the same straight line all-the time, e.g, a car moving in a straight line on a level road.

- The motion is said to be circular if the body moves on a circular path: e.g, the motion of the tip of the hand of a watch.

- The total path length covered by a moving body is the distance travelled by it.

- The difference between the final and initial position of a body is called its displacement.

- Physical quanities are of two types (i) scalar: which have magnitude only, no direction (ii) vector: which have magnitude as well as direction.

- Distance, speed, mass, time, temperature etc. are scalar quantities, whereas displacement, velocity, acceleration, momentum, force etc. are vector quantities.

- Distance travelled in unit time is called speed, whereas, displacement per unit time is called velocity.

- Position-time graph of a body moving in a straight line with constant speed is a straight line sloping with time axis. The slope of the line gives the velocity of the motion.

- Velocity-time graph of a body in a straight line with constant speed is a straight line parallel to time axis. Area under the graph gives distance travelled.

- Velocity-time graph of a body in a straight line with constant acceleration is a straight line sloping with the time axis. The slope of the line gives acceleration.

- For uniformly accelerated motion :
v = u+at

s = ut + 1/2 at²

where u = initial velocity, v = final velocity, and s = distance travelled in t seconds.