# What is the best way to find the resultant force?

#### rick99

##### New member
I have four forces that act on block. all forces act at different angle with respect to horizontal. what is the best way to find the resultant force? how should I proceed?

#### Subhotosh Khan

##### Super Moderator
Staff member
I have four forces that act on block. all forces act at different angle with respect to horizontal. what is the best way to find the resultant force? how should I proceed?
Are those co-planar forces?

Are those concurrent forces?

What are your thoughts?

Please share your work with us ...even if you know it is wrong

If you are stuck at the beginning tell us and we'll start with the definitions. Do you know the definition of functor? Where is it used?

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#### Explorer

##### New member
Start by drawing a free body diagram for the block. In your case, draw it big enough.

Draw the x and y axes on the diagram.
You don't know the direction of motion, so placing the x axis horizontal and the y axis vertical is not a bad option.

At this point look at the diagram, and find the x and y components of each force (remember that components can be positive or negative). Write them all down.

After you have done that, add all the x components, and you find the x component of the resultant force.
Do the same for the y components, and thus find the y component.

If one of the two components of the resultant force is equal to zero, or both are equal to zero, then it should simple for you to determine magnitude and direction of the force.

However, if the two components are both non-zero, draw them on a Cartesian plane. Then draw the resultant force itself.
Call θ the angle R makes with Rx.

The magnitude of the resultant force will be

R = √(Rx² + Ry²)

And the angle:

θ = arctan(Ry/Rx)

Here's a good article (how to find the resultant force) I recommend you to read.

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