Does driving a car affect the Earth's rotational velocity

Click For Summary

Discussion Overview

The discussion revolves around whether driving a car affects the Earth's rotational velocity, exploring the implications of Newton's laws of motion in this context. Participants consider the theoretical and practical aspects of this question, including the effects of acceleration, momentum transfer, and the role of external forces.

Discussion Character

  • Exploratory
  • Technical explanation
  • Conceptual clarification
  • Debate/contested

Main Points Raised

  • One participant suggests that accelerating a car east could impact the Earth's rotational speed, referencing Newton's third law.
  • Another participant counters that once a car reaches constant speed, the momentum gained is transferred back to the Earth through air resistance, resulting in no net change in angular momentum over time.
  • There is a discussion about the effects of returning to the original location, with one participant noting that north-south travel requires returning to the same latitude to restore the original Earth rotation.
  • Another participant introduces the idea that using fuel converts mass from below the Earth's surface to gases above it, potentially affecting the Earth's rotational velocity, even if the car returns home.

Areas of Agreement / Disagreement

Participants express differing views on the impact of driving on the Earth's rotation, with some asserting that the effects average out over time while others propose that mass conversion from fuel use could have an effect. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants acknowledge that the effects discussed are likely to be minimal and involve complex interactions over time, with some assumptions about momentum transfer and external forces remaining unexamined.

shott92
Messages
29
Reaction score
0
hi guys
really odd question (no such things as a silly question)
but i was just thinking about this and well according to Newtons every action has an equal and opposite reaction
well i know I am talking fractions of a degree per millenia or there abouts i guess
but when i get in my car with a mass and accelerate (lets say east)
then does this actually have an impact on the rotational speed of the earth

cheers for the time and answers :D
 
Physics news on Phys.org
shott92 said:
when i get in my car with a mass and accelerate (lets say east)
then does this actually have an impact on the rotational speed of the earth
Yes.

angular_momentum.jpg


shott92 said:
i know I am talking fractions of a degree per millenia or there abouts
You cannot accelerate your car east for millennia. As soon you reach constant speed, you are giving all the momentum you are gaining back to air, which gives it back to the Earth. And when you stop the Earth has it's original amount of angular momentum again. All the different interactions average to zero over time. Only external bodies, like the Moon can exert a "permanent" torque that reduces the Earth's angular momentum over millennia.

If you want to slow down the Earth's rotation permanently, you have move closer to the equator and stay there.
 
Last edited:
  • Like
Likes   Reactions: shott92
pretty much as i thought, thanks
although i did over think it and figured that the forces would almost equal out due to usually when you drive to a location you drive back home (return trip) lol ... forgot about braking :/
but thanks for that picture too, made me smile :D
 
shott92 said:
although i did over think it and figured that the forces would almost equal out due to usually when you drive to a location you drive back home (return trip)
For north-south travel you have to return to the same latitude to restore the original Earth rotation.

shott92 said:
forgot about braking
You don't have to actually use the brakes. The air that slows you down transfers it's momentum the Earth, with some delay though.
 
Presumably using fuel will have converted some mass (that was originally below the Earth's surface) into gasses (mass above the Earth's surface). I guess that might change the rotational velocity of the planet even if the car returns home :-)
 

Similar threads

  • · Replies 19 ·
Replies
19
Views
3K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 46 ·
2
Replies
46
Views
4K
  • · Replies 20 ·
Replies
20
Views
2K
  • · Replies 60 ·
3
Replies
60
Views
7K
Replies
9
Views
2K
  • · Replies 15 ·
Replies
15
Views
3K
  • · Replies 23 ·
Replies
23
Views
3K
  • · Replies 2 ·
Replies
2
Views
3K
  • · Replies 10 ·
Replies
10
Views
2K