Quote from: Chocolate fireguard on July 20, 2020, 04:37:40 pmQuote from: crickleymal on July 20, 2020, 04:08:55 pmQuoteIt constantly refers to escape speed as escape velocity, but nobody's perfect.I always thought it was escape velocity. I'm fairly sure that was what it was called when I did physics A levelI dare say it's still called that by some physics teachers and in some physics text books but:1 if you call something a velocity you have to include a direction (they never do) 2 the direction doesn't matter - ignoring air resistance, or on a planet with no atmosphere, you could "throw" it at escape speed in any direction from vertical to tangential to the surface and it would escape.In fact if you ignore the resistance of the planet (!) you could throw it downwards. Wait, mind blown.So if I threw something at the escape velocity/speed at just above horizontal, it would escape the gravitational pull just as successfully as if I threw it perpendicular to the ground? Surely the speed required would be greater, as the vertical component would be lower otherwise.
Quote from: crickleymal on July 20, 2020, 04:08:55 pmQuoteIt constantly refers to escape speed as escape velocity, but nobody's perfect.I always thought it was escape velocity. I'm fairly sure that was what it was called when I did physics A levelI dare say it's still called that by some physics teachers and in some physics text books but:1 if you call something a velocity you have to include a direction (they never do) 2 the direction doesn't matter - ignoring air resistance, or on a planet with no atmosphere, you could "throw" it at escape speed in any direction from vertical to tangential to the surface and it would escape.In fact if you ignore the resistance of the planet (!) you could throw it downwards.
QuoteIt constantly refers to escape speed as escape velocity, but nobody's perfect.I always thought it was escape velocity. I'm fairly sure that was what it was called when I did physics A level
It constantly refers to escape speed as escape velocity, but nobody's perfect.
So if I threw something at the escape velocity/speed at just above horizontal, it would escape the gravitational pull just as successfully as if I threw it perpendicular to the ground? Surely the speed required would be greater, as the vertical component would be lower otherwise.
Isn't that just to compensate for air resistance normally? Why space rockets launch straight up instead of tangentially like planes, which need air resistance to fly? Or at least controlled resistance. If there's no atmosphere there's no friction, and so I don't think it matters what angle it goes off at as long as it can overcome gravity. I suspect the lunar modules blasted off back to the orbiter vertically simply to minimise the amount of propellant required.
As for the lunar lander, I suspect it took off vertically rather than sideways because the rocket was on the bottom. Facetious answer I know...
Main Menu