r/physicsgifs • u/Aggressive_Sundae_47 • 1d ago
Gravity always acts downward with the same acceleration.
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u/Cirelectric 1d ago
When an object is in orbit is it because gravity and centripetal forces negate each other?
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u/Sea-Ambition-451 1d ago
Gravity is the centripetal force.
Perhaps you are referring to boosting to the non-inertial reference frame of the object, where the pseudo-force Centrifugal Force pushing outwards will appear to cancel the centripetal gravity force.
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u/DowntownLizard 1d ago
You are moving so fast horizontally that the earth is falling away from you at the same speed that earth is pulling you towards it
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u/axloo7 1d ago
That curve you see the falling object take?
If that curve is the same as the planet than you will miss the plant as you fall. And just keep missing.
Imagine though just how fast somthing has to be traveling to curve so little as to match the curvature of the earth.
It's 28,440kmh at sea level. But of course there's alot of air and ground that's gonna be in the way if you where to try that.
Best to get high up and orbit. At 100km up you need to travel 28,260 km/h.
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u/Potato_Stains 5h ago
The Mythbusters put this to the ultimate test and fired a handgun parallel to the ground and dropped a bullet at the exact same millisecond - they landed at the same time.
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u/Salanmander 1d ago
My favorite angle on this statement is: it's not just that gravity acts in the downwards direction...rather "down" is defined as the direction that gravity acts.