We usually throw a ball up. We drive cars towards a superstore. Soldiers shoot rifles to hit the enemies. Submarines float down. Train moves on its track. All these are examples of vector quantities. And now-a-days, the very common Global Positioning System (GPS) and Google Map systems represent vector quantities too.
Vector quantities are the ones that talk about the magnitude as well as the direction. Magnitude talks about the strength or length. Direction talks about where the body is pointing to or where it is directed (North, South, East, West, Left, Right, Up or Down). For Example: A person covers 10 kilometers distance, but the distance covered was in which direction needs to be specified. 10 kilometers North is a vector quantity. GPS often says, take left after 100 meters, or walk straight for 500 metres. All of these are vectors.
REPRESENTATION OF VECTORS
In Physics, we often use + or – to refer to direction. + refers to positive displacement with reference to an origin. – refers to negative displacement with reference to an origin. In 2 dimensions, vectors are often represented with magnitude and angle of direction.
EXAMPLES OF VECTOR QUANTITY
Temperature Rise/Fall: The measurement of temperature is scalar but the measurement of rise or fall in temperature is vector. For Example: 10 degrees Celsius is a scalar quantity but 5 degree fall in temperature is a vector quantity.
Velocity: Displacement of an object per second is called velocity. If I move one step left and then one step right, my net displacement is zero, and therefore my velocity is zero. Velocity is a vector quantity. Now if I go, 1 kilometers south in 1 hour, my net velocity is 1 kilometer per hour towards South. This talks about my displacement in the South direction.
Force: Here we need to specify the direction of force applied with reference to the object. 10 Newton force is a scalar quantity, but 10 Newton force in opposite direction of the moving body, is a vector quantity.
Some other vector quantities are momentum and thrust.
MANDATES FOR MEASURING A VECTOR QUANTITY
- A vector quantity should have a directional displacement. Example: 5 kilometers South.
- Origin or a reference point is mandatory. We calculate the displacement of the object, but displacement from which point? This point is called the reference point.
Thus, it is important to use vector quantity with the right direction and reference point.