News for hackers. Stuff that matters.

A comment on Voyager 1 hears the hush of interstellar plasma. Parent comment

Re:Voyager 1 hears the hush of interstellar plasma by whatshisface on Tuesday May 11, 2021 @11:09AM (#27118995)
Windup toy cars are also E=mc^2.
[ Parent | on HN ]
Re:Voyager 1 hears the hush of interstellar plasma by prewett on Tuesday May 11, 2021 @12:14PM (#27119935)
E = mc^2 implies that mass (m) is being converted to energy (E), and a windup toy car is definitely not converting mass to energy. Windup cars get their energy from torsional springs, which are E = (1/2) k theta^2.
[ Parent | on HN ]
Re:Voyager 1 hears the hush of interstellar plasma by whatshisface on Tuesday May 11, 2021 @01:05PM (#27120554)
>and a windup toy car is definitely not converting mass to energy

Ah, but it is. E=mc^2 is always true in the reference frame where the object is stationary. (We assume that we are co-moving with the windup car.) A spring under torsion is heavier than an unwound spring.

[ Parent | on HN ]
Re:Voyager 1 hears the hush of interstellar plasma by Chris2048 on Tuesday May 11, 2021 @02:18PM (#27121516)
> A spring under torsion is heavier than an unwound spring

Does it have more (invariant) mass?

[ Parent | on HN ]
Re:Voyager 1 hears the hush of interstellar plasma by whatshisface on Tuesday May 11, 2021 @03:45PM (#27122598)
Yes.
[ Parent | on HN ]