Given the x and y velocity components, how to calculate the angle?

Question

For a particle moving in a Cartesian coordinate system (neglecting the z axis), how can one calculate the angle of displacement taking into account the x and y velocity components?

Before anyone says that this is not programming, I am programming it right now, however, I do not know vector math.

For example, suppose that the values ​​of speed x and y are equal to 5.0 and -1.5, respectively, how would I calculate the angle?

Answer 1

In Javascript, I would use Math.atan2(1.5, 5.0) . To convert to degrees, use Math.atan2(1.5, 5.0)/(Math.PI/180) . Wikipedia: http://en.wikipedia.org/wiki/Atan2

Answer 2

You need atan2 :

For any non-zero real arguments x and y , atan2(y, x) is the angle in radians between the positive x-axis of the plane and the point given by the coordinates (x, y) .

Answer 3

The angle in radians along the x axis is determined by the formula:

 arctan(vy / vx); // vx > 0 

You also need to handle the case vx < 0 .

If you need a bearing against true north, then you may need:

 double bearing = 90 - arctan(vy / vx) * 360 / 2 / M_PI; 

Answer 4

The tangent arc of the tilt will give you what you want.

Answer 5

You must be careful about the angles between them. Arctangent, atan(y / x) , will give you an angle relative to the positive x-axis, but make sure you need it.

Answer 6

Angle is the arctangent of y / x. Many languages ​​have a 4-quadrant arctangent function in the math library, which takes the arguments x and y.