Rotation of Earth and falling objects

AI Thread Summary
When a ball is released from a tall building, it will land slightly to the east due to the Earth's rotation. The top of the building moves faster eastward than the bottom, allowing the ball to maintain this tangential velocity as it falls. For a 100-meter drop, the ball would land approximately 3.5 centimeters ahead of its initial vertical position after a 5-second fall. This phenomenon is attributed to the Coriolis Force. Understanding this effect highlights the impact of Earth's rotation on falling objects.
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 1 person
AKA Coriolis Force.
 
  • Like
Likes 1 person
Thanks both of you! Appreciate it. :)
 

Thread '1:1 versus 2:1 Mechanical Advantage debate'

The rope is tied into the person (the load of 200 pounds) and the rope goes up from the person to a fixed pulley and back down to his hands. He hauls the rope to suspend himself in the air. What is the mechanical advantage of the system? The person will indeed only have to lift half of his body weight (roughly 100 pounds) because he now lessened the load by that same amount. This APPEARS to be a 2:1 because he can hold himself with half the force, but my question is: is that mechanical...
View full post »

Thread 'Average velocity as a weighted mean'

Hello everyone, Consider the problem in which a car is told to travel at 30 km/h for L kilometers and then at 60 km/h for another L kilometers. Next, you are asked to determine the average speed. My question is: although we know that the average speed in this case is the harmonic mean of the two speeds, is it also possible to state that the average speed over this 2L-kilometer stretch can be obtained as a weighted average of the two speeds? Best regards, DaTario
View full post »

Thread 'Newton's first law?'

Some physics textbook writer told me that Newton's first law applies only on bodies that feel no interactions at all. He said that if a body is on rest or moves in constant velocity, there is no external force acting on it. But I have heard another form of the law that says the net force acting on a body must be zero. This means there is interactions involved after all. So which one is correct?
View full post »

Similar threads

I How to Land a Tree Flat in 3/4 Rotation: Solving the Equations
Replies
19
Views
2K
Coriolis effect causes in motion of a free falling object
Replies
7
Views
5K
B Inertia and flying
Replies
23
Views
2K
Centrifugal force on Earth and deviation of free falling obj
Replies
6
Views
3K
Earth's rotation having effect on sub-orbital trajectory
Replies
7
Views
2K
I Normal force and details of the Earth holding up an object
Replies
12
Views
2K
Free fall detect of rotating object
Replies
10
Views
3K
Some Flight Calculations and the Motion of the Earth
Replies
11
Views
2K
Would a Very Large Mass (e.g. the Moon) Fall with g?
Replies
11
Views
2K
Relative speed and coin dropping
Replies
10
Views
2K

Hot Threads

Recent Insights

Back
Top