Au contraire - that is very useful physics knowledge
not being someone who studied the subject it's always interesting to know when oft quoted physics are wrong or misleading - damn you Twilight Zone.
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maiden is filmed before a live studio audience,
Mon 1 Dec 2003, 7:55,
archived)
it's true most of the time
but there's a momentum term as well.
the simplification is true for general relativity, which is often good enough
(
kitty meow meow,
Mon 1 Dec 2003, 7:59,
archived)