Determine the heading of the object in question. The heading may be measured with a compass or protractor.
Draw a diagram on paper such that the object is at the center of the compass and a vector representing its speed is emanating from it in the heading indicated.
Create a right triangle with the heading and velocity information to set up the calculation of component velocities. The net directional velocity becomes the hypotenuse of the right triangle, with the unknown component velocities represented by the two sides. The right angle of the triangle must be positioned so that one of the sides is parallel to 0 degrees and the other 90 degrees. This is the triangle formed when a perpendicular is dropped from the end of the net velocity vector to a line at 0 degrees.
Calculate the component velocities using trigonometric functions. For one leg, set up an equation to solve for the unknown velocity:
cos(heading) = (unknown velocity adjacent to heading angle)/(net velocity).
For the other leg, replace the cosine with the sine function:
sin(heading)=(unknown velocity opposite heading angle)/(net velocity).