Time for object to fall length of 10m rope, assuming g=10m/s

In summary, the conversation discusses spacetime curvature and spacetime intervals in a scenario where an apple is cut loose from a tree but remains attached by an unstretchable rope. The relevant events and their corresponding distances and times in both the tree frame and the apple frame are mentioned. The possibility of using either Newton's or Einstein's theory to calculate the effects is also brought up. The conversation ends with a clarification of the acceleration unit and a suggestion to use formulas from a given source for calculations.
  • #1
gabeeisenstei
37
0
I'm still struggling with spacetime curvature. I want to know about the spacetime intervals in the following scenario:
An apple is cut loose from a tree, but is still attached by an unstretchable rope that is measured to be 10 meters by the tree observer.

(I'm ignoring all but relativistic effects. I'm also assuming that initial gravitational acceleration from the given location is exactly 10 m/s. I'm not interested in detailed calculations, just the relevant (in)equalities.)

Event1: apple cut loose from tree at t=0
Event2: clock at original apple position ticks 1 second
Event3: rope yanks on tree after apple falls rope length
Event4: rope yanks on apple


Spacetime intervals,
according to tree frame:
E1-2: distance=0, (proper) time=1s
E1-3: distance=0, time=1?
E1-4: distance=10m, time=1?
E3-4: distance=10m, time=0? or E4 sooner by S.R.?
E2-3: distance=0, time=?

according to apple frame:
E1-2: distance>10m, time<1s (so velocity of clock>10m/s ?)
(S.R. effect also slows tree clock)
E1-3: distance>10m, time=?
E1-4: distance=0, proper time=?
E3-4: distance>10m, time=0? or E3 sooner by S.R.?
E2-3: distance>10m?, time=?
 
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  • #2
The GR effect on the scales you propose is extremely small, do you want a calculation using Newton's or Einstein's theory?

By the way you state the acceleration in units of measure of m/s which is not correct.

You can actually use the formulas from:
https://www.physicsforums.com/showthread.php?t=552878
if you want to calculate things using GR.
 
  • #3
Yes I know the effect is small. If you prefer we can say that the apple is outside the horizon of a black hole and change 10 meters to something much bigger, but as I said I am not looking for the full calculations, just the inequalities.
(And yes I meant acceleration of m/s^2, attaining 10 m/s in one second.)
 

1. What is the formula for calculating the time for an object to fall?

The formula for calculating the time for an object to fall is t = √(2h/g), where t is the time in seconds, h is the height in meters, and g is the acceleration due to gravity (usually 9.8 m/s² on Earth).

2. How do you calculate the length of a 10m rope?

The length of the 10m rope in this scenario is not directly related to the time for an object to fall. However, if the rope is hanging straight down with one end held at a certain height, the length of the rope can be calculated using the Pythagorean theorem: L = √(h² + 10²), where L is the length of the rope and h is the height in meters.

3. Does this calculation assume any other factors besides gravity?

In this scenario, the calculation assumes that there is no air resistance, wind, or other external forces acting on the object. It also assumes that the rope is a straight line and that gravity is constant.

4. How accurate is this calculation?

This calculation is relatively accurate for theoretical purposes, but in real-life situations, there may be slight variations due to external factors such as air resistance or variations in the acceleration due to gravity. Additionally, the rope may not be a perfect straight line, which could also affect the accuracy of the calculation.

5. Can this formula be used for objects of any weight?

Yes, this formula can be used for objects of any weight, as long as the acceleration due to gravity remains constant and there are no external factors affecting the fall.

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