They also talk about the maximum power c^5/4G and the maximum mass flow rate c^3/4G.
I wonder whether a maximum mass flow rate limits the speed of a Lamborghini. A Lamborghini is about L=4 m long, weights M=1000 kg. With a maximum mass flow rate its resulting maximum speed is V = c^3/4G * L/M...
The number of papers on maximum force c^4/4G and similar limits in general relativity is growing. Last year there were
A. Jowsey et al, arXiv:2102.01831
V. Faraoni, Phys Rev D 103, 124010 (2021)
C. Schiller, Phys Rev D 104, 068501 (2021)
V. Faraoni, Phys Rev D 104, 068502 (2021)
C. Schiller...