How Does General Relativity Explain an Object Thrown Up Returning Back?

AI Thread Summary
General Relativity explains that when an object is thrown upward, it follows a geodesic path in curved spacetime, which is influenced by gravity. The object travels in an arc resembling an ellipse, and if not for the ground, it would continue in that path indefinitely. The discussion emphasizes that gravity is not just about spatial curvature but also involves the time dimension, which is essential for understanding mass attraction. The importance of visualizing gravitational acceleration in spacetime is highlighted through interactive resources. Overall, the conversation clarifies misconceptions about gravity's role in vertical motion.
rajeshmarndi
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I could understand gravity involve in object revolving around a big mass as the path of the object is circular.

But couldn't understand how gravity is explained when an object thrown up returns back.
 
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hi rajeshmarndi! :smile:

are you also happy about an orbit where the path is elliptical?

when you throw an object almost vertically, it follows an arc of an ellipse until it hits the ground …

if the ground wasn't there, it would orbit in that ellipse forever​

when you throw an object exactly vertically, if the ground wasn't there, it would go up and down forever in a "flat ellipse" :wink:
 
rajeshmarndi said:
I could understand gravity involve in object revolving around a big mass as the path of the object is circular.

But couldn't understand how gravity is explained when an object thrown up returns back.

Geodesic path in curved spacetime for a vertical throw.
http://www.relativitet.se/spacetime1.html
 
thanks A.T, for providing the link also.
It was helpful what i was searching.
 
rajeshmarndi said:
thanks A.T, for providing the link also.
It was helpful what i was searching.
Here is an interactive version of that, where you can thow it up and let it fall into a tunnel through the planet:
http://www.adamtoons.de/physics/gravitation.swf
 
A convenient way to remember how gravitational acceleration looks in spacetime is, which summarizes some detailed mathematics, is (with time on one axis and space on two others):

constant velocity appears as a straight line,

constant linear acceleration appears as a smooth curve, (say. an freely falling object)

constant rotational acceleration appears as a corkscrew (say, the Earth rotating about the sun)
 
AT -

thanks again, its really a new way users like me to have a look at space-time curve.
 
rajeshmarndi said:
AT -

thanks again, its really a new way users like me to have a look at space-time curve.

The title of the thread suggests that you might have had the misconception that it's the curvature of space only, that models gravity in General Relativity. But in fact the time dimension is crucial to understand the key effect of gravity: mass attraction.

Have a look at this:
http://www.physics.ucla.edu/demoweb..._and_general_relativity/curved_spacetime.html
 
rajeshmarndi said:
I could understand gravity involve in object revolving around a big mass as the path of the object is circular.

But couldn't understand how gravity is explained when an object thrown up returns back.
I guess, that is acceleration due to gravity.When an object is thrown vertically up then,it come down it caused gravity . Gravity always attractive. And it always directed to the earth.
 
  • #10
i could not understan about this given problem.. " A car travels up a nill at a constant speed of 37 km/h & return down the hill at a constat speed of 66 km/h. Calculate the average speed for the whole trip."
Can somebody help me answer this?,,, thaks a lot...
 
  • #11
The last two posts seem to have missed the point completely- that this is about the General Relativity picture of gravity.

kyrdmenchou, please do NOT 'hijack' another person's thread to ask a completely different question. Your question has nothing at all to do with gravity. I will answer your question by p.m.
 

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