Rotation of Earth and falling objects

  • Context: Undergrad 
  • Thread starter Thread starter ViolentCorpse
  • Start date Start date
  • Tags Tags
    Earth Falling Rotation
Click For Summary

Discussion Overview

The discussion centers around the behavior of a ball released from a tall building in relation to the Earth's rotation. Participants explore whether the ball will land ahead in the direction of the Earth's rotation or lag behind as the Earth moves beneath it. The scope includes conceptual reasoning and basic calculations related to physics and motion.

Discussion Character

  • Exploratory, Conceptual clarification, Mathematical reasoning

Main Points Raised

  • One participant proposes that the ball should land ahead to the east because it retains the tangential velocity of the building's top as it falls.
  • Another participant agrees, stating that the ball continues to carry the excess eastward velocity during its fall, leading to a landing position to the east.
  • A participant mentions the Coriolis Force in relation to the discussion, suggesting a connection to the observed effect.

Areas of Agreement / Disagreement

Participants generally agree that the ball will land to the east, but the discussion does not delve into potential counterarguments or alternative perspectives on the effect of Earth's rotation.

Contextual Notes

The discussion does not address potential influences such as air resistance or the exact conditions under which the observations hold true, leaving some assumptions unexamined.

ViolentCorpse
Messages
190
Reaction score
1
Hello everyone!

If a ball is released from the top of a very tall building, would it land ahead in the direction Earth is rotating (to the east) or would it lag behind i.e the Earth "moves out" from underneath it so it lands to the west? I think it should land ahead to the east since its tangential velocity is greater than that of the ground, but I'm not sure.

Thank you very much!
 
Last edited:
Physics news on Phys.org
Yes, all things being equal, it would land to the east. As you point out, the top of the building is moving slightly faster eastward than the bottom and ball continues to carry this excess as it falls.

Back of the envelope...

For a 100 meter building the fall will nominally take 5 seconds (neglecting air resistance). The Earth is rotating at 2pi radians in just under 24 hours. With a 100 meter delta in radius, that's about 7 millimeters per second. Over a 5 second fall that would amount to about 3.5 centimeters.
 
  • Like
Likes   Reactions: 1 person
AKA Coriolis Force.
 
  • Like
Likes   Reactions: 1 person
Thanks both of you! Appreciate it. :)
 

Similar threads

High School Inertia and flying
  • · Replies 23 ·
Replies
23
Views
3K
Undergrad How to Land a Tree Flat in 3/4 Rotation: Solving the Equations
  • · Replies 19 ·
Replies
19
Views
2K
Undergrad On whether the motion of a Foucault pendulum bob is comparable to ballistics
  • · Replies 10 ·
Replies
10
Views
3K
Undergrad Ball free fall 100m at equator, where is the landing spot?
  • · Replies 45 ·
2
Replies
45
Views
5K
Undergrad Speed of the umbra during eclipse vs rate of the Earth's rotation
  • · Replies 3 ·
Replies
3
Views
2K
Undergrad Dinosaur question -- Was Earth's gravity lower in the past?
  • · Replies 5 ·
Replies
5
Views
4K
Graduate Centrifugal force on Earth and deviation of free falling obj
  • · Replies 6 ·
Replies
6
Views
4K
Graduate Earth's rotation having effect on sub-orbital trajectory
  • · Replies 7 ·
Replies
7
Views
2K
Graduate Coriolis effect causes in motion of a free falling object
  • · Replies 7 ·
Replies
7
Views
5K
Undergrad Normal force and details of the Earth holding up an object
  • · Replies 12 ·
Replies
12
Views
2K