A force is a vector quantity which has both magnitude (size) and direction. Thus, the operations (for example, addition and subtraction) carried out on forces are not merely taking two numbers and adding / subtracting them. As directions are involved, angles have to be taken into consideration when performing operations on forces (and other vector quantities).

The resolution of a force is the separation of a single force into its components with different directions - usually perpendicular to one another. The resolution (separation) of a force into its components facilitates (helps in) the computations / calculations needed to be carried out.

Very often, trigonometry is used to help resolve forces into their components.

Consider the following:


The object (block) of mass, m,  is resting on a horizontal plane. The object has the force of gravity (weight, W = mg) acting upon it. Weight is a force that acts directly straight down to the centre of the Earth - a vector quantity represented by the red arrow.

Click on the diagram to continue.

     
Daya merupakan kuantiti vektor yang mempunyai magnitud dan arah. Justeru itu, operasi (seperti hasil tambah dan hasil tolak) yang dilakukan ke atas daya bukan semata-mata mengambil dua nombor dan menjalani proses campur atau tolak. Oleh kerana arah perlu dipertimbangkan, sudut-sudut perlu diambil kira apabila melakukan operasi ke atas daya (dan kuantiti-kuantiti vektor yang lain).

Resolusi daya merupakan peleraian satu daya kepada komponen-komponennya dalam arah berlainan - lazimnya pada arah bersudut tepat dengan satu sama lain. Resolusi (peleraian) daya kepada komponen-komponennya memudahkan pengiraan / komputasi yang perlu dilakukan.

Biasanya trigonometri digunakan untuk membantu meleraikan daya kepada komponen-komponennya.

Apabila sebuah objek diletakkan pada satah mendatar, ia akan mengalami daya graviti (berat, W = mg). Berat merupakan daya yang bertindak secara menegak - terus ke arah pusat Bumi.