How to draw the oblique throw trajectory of an object in AutoCAD/GStarCAD

I will show you, how to draw oblique throw trajectories with LitioLAB. This is based in the general oblique throw formulas - parabolic movement.



Check the following video:




The general formulas that describe the oblique throw are as follows:

    X = X0 + V0x*t
    Y= Y0 + V0y*t+1/2*g*t^2
    with g = -9.8 m/s^2



We can use LitioLAB’s auxiliary constants to enter the initial speed and the initial angle as follows:

    C1 = V0
    C2 = angle



We can use the auxiliary formula boxes to enter the initial position, as follows:

    J1 = x0
    J2 = Y0



Following, the examples with the data as from the video:

For our first example let’s assume we have an athlete that throws a ball with an initial speed of 14 m/s at a 45° angle, and the starting height of the ball’s trajectory being 2 m. That is:

C1 = V0 = 14
C2 = alfa = 45°
J1 = X0 = 0.0 m
J2 = Y0 = 2.0 m

And the formulas for X and Y:
X = J1 + C1*cos(c2)*u
Y= J2 + C1*sin(c2)*u +0.5*(-9.8)*u^2

NOTE: It is important to be consistent in the selection and use of units and constant values. If we use meters as length unit, and meters per second as speed unit, we also should use g in meters per centimeter square. And thus, the parameter u will also represent seconds.

The next example is a ball falling from a roof with a slope of 45 degrees, from a height of 18 m. Let’s assume that at the moment it comes to the roofs edge, the ball has a speed of 12 m/s.

Last example: A plane flying at a height of 2000 m at a speed of 800 km/h (which is 222,2 m/s), releases a bomb.



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