On 19/12/22 9:24 am, Stefan Ram wrote:
So what's the time until a mass of one gram arrives at the ground versus a mass of ten grams? I think one needs "Decimal" to calculate this!
Or you can be smarter about how you calculate it. Differentiating t with respect to m gives dt/dm = -0.5 * sqrt(2 * s * r**2 / (G * (M + m)**3)) which, since m is much smaller than M, is approximately -0.5 * sqrt(2 * s * r**2 / (G * M**3)) So >>> G = 6.6743015E-11 >>> r = 6.371E6 >>> M = 5.9722E24 >>> dtdm = -0.5 * sqrt(2*s*(r**2) / (G * M**3)) >>> dtdm * (1/1000 - 10/1000) 3.4004053539917275e-28 which agrees with your Decimal calculation to 3 digits, and should be as precise as the input numbers (about 4 digits in this case). This is a good example of why it's important to choose an appropriate numerical algorithm! -- Greg -- https://mail.python.org/mailman/listinfo/python-list
