public void SteadyMotionTest()
{
var t = 5;
var s = 35;
var v = 7;
Assert.AreEqual(t, SteadyMotion.GetDuration(s, v));
Assert.AreEqual(s, SteadyMotion.GetDistance(v, t));
Assert.AreEqual(v, SteadyMotion.GetVelocity(s, t));
}
/// <summary>
/// Find t in s = 0.5*a*t² + v0*t
/// </summary>
/// <param name="s">The distance [m].</param>
/// <param name="a">The acceleration [m/s²].</param>
/// <param name="v0">The initial velocity [m/s].</param>
/// <exception cref="NegativeValueException">Thrown, if the given distance will never be reached.</exception>
/// <returns>Returns the duration [s].</returns>
public static Durations GetDuration(double s, double a, double v0)
{
if (a == 0)
{
var t = SteadyMotion.GetDuration(s, v0);
return(new Durations(t, t));
}
var sqrt = 2 * a * s + v0 * v0;
if (sqrt < 0)
{
throw new NegativeValueException($"The distance {s}m will never be reached starting with a velocity of {v0}m/s and accelerating with {a}m/s²");
}
var t1 = (-Math.Sqrt(sqrt) - v0) / a;
var t2 = (Math.Sqrt(sqrt) - v0) / a;
var durations = new Durations(t1, t2);
return(durations);
}