Scalar and Vector are the quantities used in physics terminology. A scalar quantity is a quantity which has only magnitude and only single dimensional while vector quantity has both the magnitude and direction and it was multidimensional. Lets take a brief look about scalar and vector and their differences.
Vector:
In motion vector is an important factor to understand. Physical quantity which has magnitude and direction both and which obey triangle law are called vector quantities. Vector can be written as boldface letter and can be drawn as an arrow with the head and tail and the length of the arrow defines the magnitude of the vector quantities.
Example of a vector quantity are displacement, velocity, acceleration for Momentum torque etc.
Electric current though has a direction it is a scalar quantity because it does not obey triangle law. Moment of inertia, pressure, refractive index and stress are tensor quantity.
Scalar:
Physical quantities which have magnitude only and no direction are called scalar quantities. Example mass, speed, volume work, power, energy etc.,
Some of the scalar and vector factors in Motion are:
Distance:
Distance is the length of actual path covered by moving object in a given time interval. It is scalar quantity. It is always positive.
Displacement:
Shortest distance covered by a body in a definite direction is called displacement. It is a vector quantity. It may be positive negative or zero both having the same unit.
Speed:
Distance travelled by the moving object in a time interval is distance called speed
speed = distance / time
Velocity:
Velocity of moving object is defined as the displacement of object in unit time interval velocity = displacement / time.
It is a vector quantity.
Difference between Scalar and Vector:
| Scalar | Vector |
|---|---|
| Definition | |
| Scalar quantity is defined as the physical quantity with magnitude and no direction | It is defined as physical quantity with both magnitude and direction |
| Examples | |
| Mass, speed, distance, time, area, volume etc., | Acceleration displacement, momentum, force etc., |
| Representation | |
| Scalar quantity is represented by a number and a unit | vector quantity is represented by a Arrow at the top and a unit |
| Direction | |
| It has no Direction | It has Direction |
| Can we calculate it? | |
| scalar can be added any type | Vectors can be added geometrically but not algebraically |
Conclusion:
Velocity is a vector quantity that specifies both a direction as well as a magnitude while speed is a scalar quantity. The speed is the magnitude of the velocity. A train has a 120 Kmph velocity and it’s speed would be 120Kmph.
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