I could have done with the first tool (Newtonian acceleration) when I was writing (the now deleted) prologue** of WiP1
** - This had a small craft loose inside a hanger of a ship, when the ship, without warning, started to decelerate (at a known set rate and would then increase its rate of deceleration -- to another fixed rate -- a fixed time later, bringing the loose craft ever closer to an unpleasant meeting with a near indestructible barrier beyond the hangar doors. The hangar doors face forwards, but into an area of the ship that's open to space. In the meantime, the character, the pilot of the craft, had to try and decelerate his own craft (while being handicapped by a safety feature that stopped the craft using its main engine while inside the hangar). I did my calculations with a spreadsheet, but was always a bit suspicious of my workings***. The event still happens, but is not shown (and, as yet, is not mentioned to any other character).
*** - I wanted to make the figures realistic, given what the character had to do in the time available) and was being driven by the need for it all to take a certain time (so I was having to do it all backwards: working out the two rates of acceleration of the ship and the duration between the start of the first and the start of the second, the rate of deceleration that the small craft might be able to achieve...).
