why are Ax =A costheta ?
Answers
ADDING VECTORS
Adding vectors can be done graphically, but this can get messy. The best way is the component method.
First define an x and y axis for your system - the choice is up to you.
Find the x and y component of the vectors you wish to add. Be very careful, there are some tricks here:
Make sure your calculator is in the proper mode (degrees or radians)
Are your angles measured from the x or y axis? To keep things simple, it is probably best to have all your angles measured from the x-axis.
If your angles are measured from the x axis, you can always use the same formula for the x and y components: Ax = A cos (theta) Ay = A sin(theta)
Check the sign of the component. No matter how you calculate your component - check the sign. If it is going in the negative y direction, makes sure the y-component is negative
Add components - that is the x-component of the resultant is the addition of the x-components - same for y
To Find the length of the resultant - use the pythagorean theorm
To find the angle (from the x-axis) you can use theta = inverse tan (Ry / Rx)
HOPE IT HELPS