137
Special theory of ruletivity
(lemmy.world)
you are viewing a single comment's thread
view the rest of the comments
view the rest of the comments
this post was submitted on 14 Jul 2023
137 points (100.0% liked)
196
16543 readers
2643 users here now
Be sure to follow the rule before you head out.
Rule: You must post before you leave.
founded 1 year ago
MODERATORS
I know it’s largely made up for parody but the teacher’s point is true. The “student” showed no work, but rather used an unexplained and underived formula.
But yeah “ha ha—teacher so stupid”
It’s the relativistic velocity addition formula, which makes zero sense in non-relativistic scenarios, but it’s useful because it caps the velocity addition to just below c.
EDIT: I misread. Yeah, even if correct you can’t just write down a formula and use it without justifying what it does or where it comes from.
Of course you can, if the formula is well-known and its applicability is obvious. To use a question a bit more at the appropriate level, if the question was "Justin was sitting on a bus travelling at 50 mph. He has been moving for 12 minutes, how far has he travelled?" you wouldn’t expect the student to write "the formula to calculate distance given speed and time is speed x time, therefore distance = 50 x 1/5 = 10 miles".
No, you’d just expect "distance = 50 x 1/5 = 10 miles". Or maybe at most "distance = speed x time = 50 x 1/5 = 10 miles", but even that is overkill if the student has demonstrated understanding via the former.
You’re absolutely right. I probably should have specified that in this context, that formula comes completely out of the blue and is not really appropriate, so I feel like in this case it warrants a bit of explanation.