NCERT 11th Class : Motion In a Plane -II : Motion in 2D using Vectors

Average Velocity : The average velocity is the ratio of displacement and corresponding time interval. The direction of velocity is same as that of displacement vector. i.e. the direction of velocity at any point on the path of an object is tangential to the path at that point and is in the direction of motion.

Instantaneous Velocity : It is given by the limiting value of the average velocity as the time interval approaches zero or it is the velocity at any point on the motion path.

Average Acceleration : The average acceleration of an object for a time interval moving in x-y plane is the change in velocity divided by the time interval. 

 

Instantaneous Acceleration : It is the limiting value of the average acceleration as the time interval approaches zero.

Equations of motion for uniform acceleration : Motion in a plane (two-dimensions) can be treated as two separate simultaneous one-dimensional motions with constant acceleration along two perpendicular directions. Hence all the equations of motion will have two components.