en.wikipedia.org/wiki/Railgun
2 corrections found
Germany, France and Japan will jointly develop a railgun weapon.
Japan’s May 30, 2024 defense agreement with France and Germany was a railgun-technology cooperation framework, not a commitment to jointly develop a railgun weapon.
Full reasoning
The official Japanese Ministry of Defense announcement says the parties signed "Implementation Guidelines for Cooperation on Railgun Technologies". It explains that the purpose is to facilitate exchange of information and opinions and examine the possibility of collaboration in railgun-technology research, development, testing, and evaluation. That is materially narrower than saying the three countries "will jointly develop a railgun weapon".
In other words, the official record describes a technology-cooperation and feasibility framework, not a definitive trilateral weapon-development program.
2 sources
- 防衛省、フランス国防省、ドイツ連邦国防省及び仏独サン=ルイ研究所による「レールガン技術の協力に係る実施要領」に関する署名について
本実施要領は、参加機関間のレールガン技術に関する情報・意見交換を円滑に進めることでレールガン技術に関する研究・開発・試験・評価の協業の可能性を検討することを目的とするものです。
- Acquisition, Technology & Logistics Agency : Ground Systems Research Center
This is the research on railgun how guns’ capability can be upgraded by using electric energy. ... The research is being undertaken between Japan and U.S. as a co-operative research project.
By definition, if a current of one ampere flows in a pair of ideal infinitely long parallel conductors that are separated by a distance of one meter, then the magnitude of the force on each meter of those conductors will be exactly 0.2 micro-newtons.
That was the old SI definition of the ampere. Since the 2019 SI redefinition, the ampere is defined via the elementary charge, not by the force between parallel conductors.
Full reasoning
This sentence reflects the pre-2019 SI definition of the ampere. Under the current SI, the ampere is defined by fixing the numerical value of the elementary charge (e), not by the force between two infinitely long parallel wires.
NIST explicitly says that until 2019 the ampere’s official definition was the hypothetical parallel-conductor force experiment. The BIPM’s current SI definition page defines the ampere by fixing the value of the elementary charge. So the article’s wording is outdated and incorrect as a statement of what is true "by definition" today.
2 sources
- Ampere: Introduction | NIST
Until 2019, its official definition ... specified a completely hypothetical situation: The ampere is that constant current which ... would produce between these conductors a force equal to 2 x 10^-7 newton per meter of length.
- ampere - BIPM
The ampere, symbol A, is the SI unit of electric current. It is defined by taking the fixed numerical value of the elementary charge e to be 1.602 176 634 x 10^−19 when expressed in the unit C, which is equal to A s.