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Vector Quantities

The physical quantity which can be completely described by the magnitude of the quantity and with the direction completely are called the vector quantities. For example, weight, force etc. But, as we know that the electric current has a particular direction in which it flow. So, it mean that the electric current is a vector quantity. But, the electric current is a scalar quantity because it does not obey the law of vector addition. So, for a vector quantity, it is compulsory that it obeys the law of vector addition. Here we discuss some of the vector quantities.

Velocity a Vector Quantity in Physics :

Velocity is the ratio of the displacement and the time taken to cover that displacement. As we know that the displacement is also a vector quantity. The velocity of a particle may be zero, positive or negative according to the direction of the displacement. If the displacement in the body is in the right direction from the origin, then the displacement is positive and hence velocity is positive. If the displacement in the body is in the left direction from the origin, then the displacement is negative and hence velocity is negative. As any particle completes one round to and fro then the displacement is zero so that the velocity is also zero. 


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Force a Vector Quantity in Physics :

Force is a pull or push so that the state of the body changes or tends to changes. According to the Newton’s second law, the force is equal to the product of mass of the body and the acceleration produced in the body. As we know that the acceleration is a vector quantity so that the force is also a vector quantity. If the force acting on a particle is in any arbitrary direction, then to find the force in any particular direction, we have to resolve the components of force. For example, a force of 20 Newton acts on a particle at an angle of 30° with the X-axis


Vector Quantity   


Image of a force acting on the particle at an angle 30° with the X-axis

So the force in the X-axis direction is F Cos 30° = 20 (/2) = 10  Newton, and the force in Y-axis direction is F Sin 30° = 20 (1/2) = 10 Newton.


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Conclusion to Vector Quantity in Physics :

To conclude, vector is a physical quantity that has magnitude as well as a direction. It can have value as positive, negative and zero. There are many examples of vectors such as velocity and force which work on the principles of the vector quantity.