Are Batteries Heavier When They're Full? (with Robert Llewellyn!)

Robert Llewellyn is lovely! He agreed to drive me at 135mph for this video, and I was in a remote controlled car that he drove over on his channel. Go see: • Autonomous Off Road Ve... !
And thank you to the physicists I pestered about this one. For a definitive, complicated, physics-based answer, see Luboš Motl's post here, which a couple of people referred to: physics.stackex...
And, of course, thank you to our wonderful camera crew: Matt Gray, mattg.co.uk or / unnamedculprit , and Mark Hankins from Hankin Films.
More from me: tomscott.com - / tomscott