How Does the Rain Frame Affect Perception of a Ball Falling Off a Cliff?

In summary: This means that the raindrop can still be considered stationary and the floor can still be considered accelerating upwards to meet the raindrop, as long as the ball is not rolling. However, if the ball is rolling, then the floor must be moving away from the raindrop to make sure it leaves before the raindrop converges with the floor in spacetime.
  • #1
FallenApple
566
61
Shellframe.gif


So a ball is rolling off a cliff. The red is the proper acceleration and the blue is the geometric acceleration. How is it in the rain frame that the surface is moving down initially?

Consider the situation where a rain drop falls straight down, with no ball rolling, just the ground right below. When the raindrop falls, since gravity is a pseudo force, we can consider the raindrop as stationary and the floor as accelerating upwards to meet the raindrop. This makes sense because the surface of floor will have an unbalanced pressure from the bottom pushing to the top, making the patch on the surface have a proper acceleration vector of up, accelerating it though spacetime to meet the rain drop. Hence from the rains perspective, the ground needs to be seen moving up.

So why all of the sudden, when there is a ball rolling off of a cliff, the situation is changed? What if the ball is just not rolling?, then the ground would be accelerating away from the raindrop forever, which doesn't make sense.

Is it because the water drop has to hit the floor of the top of the cliff after the ball has fallen off in order for the whole frame to be internal? So while the water is in free fall, the ball still needs to fall off first. Could this mean that the whole floor has to move away to make sure that the ball leaves the cliff before the floor converges with the raindrop in spacetime?

Here is the site

https://en.wikipedia.org/wiki/Proper_acceleration
 
Last edited:
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  • #2
Did you read the note below the image?
 
  • #3
Orodruin said:
Did you read the note below the image?
Yes. But it didn't explain why from the viewpoint of the rain, the floor must accelerate down first.
 
  • #4
FallenApple said:
Yes. But it didn't explain why from the viewpoint of the rain, the floor must accelerate down first.
As said in the note, it is not the frame of a rain drop, rather it is a frame of a free falling ball that starts moving upwards in the Earth frame.
 

Related to How Does the Rain Frame Affect Perception of a Ball Falling Off a Cliff?

1. What causes a ball to fall off a cliff?

The force of gravity causes a ball to fall off a cliff. Gravity pulls all objects towards the center of the earth, including the ball that is dropped off the cliff.

2. Will the ball fall at a constant speed?

No, the ball will not fall at a constant speed. As the ball falls, it gains speed due to the acceleration of gravity. However, air resistance may also play a role in slowing down the ball's descent.

3. How does the height of the cliff affect the time it takes for the ball to fall?

The height of the cliff does not affect the time it takes for the ball to fall. The time it takes for an object to fall is determined by the acceleration of gravity and the initial velocity of the object. As long as the initial velocity is the same, the time it takes for the ball to fall will be the same regardless of the height of the cliff.

4. What is the velocity of the ball when it reaches the bottom of the cliff?

The velocity of the ball when it reaches the bottom of the cliff will depend on various factors such as the initial velocity, the height of the cliff, and air resistance. However, using the equation v = √2gh, where v is the final velocity, g is the acceleration of gravity (9.8 m/s²), and h is the height of the cliff, we can calculate the velocity of the ball at the bottom of the cliff.

5. Can a ball fall off a cliff and then go back up?

No, a ball cannot fall off a cliff and then go back up on its own. The force of gravity will continue to pull the ball towards the ground, causing it to fall downwards. However, if there is an external force acting on the ball, such as a gust of wind, the ball may appear to go back up momentarily, but it will eventually continue to fall due to gravity.

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