Distance: It is the change of position of a body. Its si unit is mitres. It is a scalar quantity .

Displacement: It is a change of position of a body (in a particular direction). Its si unit is mitres. It is vector quantity.

Vector quantity: These are the quantities which have both magnitude and direction. Eg: force, acceleration , weight , etc.

Scalar quantity: These are the quantities which have magnitude only . eg: mass, time,speed,etc.

Quantity: These are the parameters of physics , which is internationally recognized to quantify things. Eg: luminosity,length,etc.

Velocity: It is the rate of change of displacement with time. Its si unit is mitre/second. It is vector quantity.

quantity	equation
speed	Distance/time
velocity	Displacement/time
Average speed	Total distance travelled/total time
Instantaneous velocity	Accertain distance/accertain time

 

Acceleration: It is the rate of change of velocity with time. Its si unit is m/s2. It is a vector quantity.

Deceleration: It is the rate of change of velocity with time , opposite to the direction of motion. Its si unit is m/s2. It is a vector quantity.