How can I calculate the net force of an object?

What is the meaning of net force?

• Net force means the resultant.

• It's very easy to find resultant , if you have knowledge in trigonometry.

Here you can see where the resultant force of each object acts

• In below image consider the object in left hand .(Here you have to deal with angles)

• In first image all forces are act in vertical direction, but in situation ##A## It's not, so we have to get the resultant .

• Resolving forces to the horizontal direction ##150N cos ## ##30^.##- ##60N##

• Resolving forces to the vertical downward direction ##196N## - ##121N##.

• Why we resolved it horizontal direction & vertical direction?

  • When finding resultant we should resolve forces into perpendicular direction.
    • Why we should resolve forces into perpendicular direction?

Consider the image below,

##F##= Resultant force.

In situation ##A## , what is ##F_x## and ##F_y## ?

• ##F_x## = ##60N##

• ##F_y## = -##121N##,

• So to find the resultant force we need both direction and magnitude ,because force is a vector quantity

So here

• Magnitude of resultant here is ##(18241)^(1/2)##= ##135N##
• Direction of resultant= ##arctan##(2) = ##63.43.## degrees to the horizontal.

Then in situation ##A## magnitude of net force is 135N and it is inclined ##63.43.## degrees to the horizontal.

Likewise you can calculate resultant.