Freefall Acceleration of a Raindrop

Click For Summary

Homework Help Overview

The discussion revolves around the freefall acceleration of a raindrop falling from a height of 1700 meters, specifically examining the effects of gravity and the implications of ignoring air resistance in calculating its velocity.

Discussion Character

  • Exploratory, Assumption checking

Approaches and Questions Raised

  • The original poster attempts to calculate the time and velocity of a raindrop using kinematic equations, questioning the reasonableness of the resulting velocity without considering air resistance.

Discussion Status

Some participants acknowledge the calculations provided by the original poster, while others suggest that air resistance must be considered for a more realistic assessment of the raindrop's velocity. There is an exploration of different factors affecting the fall velocity.

Contextual Notes

Participants note the unrealistic nature of ignoring air resistance in this scenario and reference Stokes' law for a more accurate understanding of the fall velocity of small spheres in a fluid.

VinnyCee
Messages
486
Reaction score
0
I have an answer that does not seem right:

The raindrop falls from 1700m high with constant acceleration of 9.81 m / s^2
What is the velocity of the raindrop not considering any resistance?

i used y - yo = vo * t - (1/2) g t^2 to get the time to hit the ground at 18.62 seconds.

I then plugged that into v = vo + a t to get 182.63 m / s which seems kind of fast for a raindrop, right? Can anyone help? Please?
 
Physics news on Phys.org
So that would imply, that in reality, you cannot ignore air resistance, if you want a meaningful value for the velocity of a rain drop. I did not check your numbers but they do not seem unreasonable, for this ideal but unrealistic scenario.

Edit, checked your numbers they are right in all of the signifiant digits.
 
Last edited:
Thank you for the help :approve: I always get worried that I did something wrong when numbers do not turn out to appear reasonable.
 
Check out Stokes' resistance law on a sphere moving through a viscous fluid.
This yields a fall velocity consistent with experiments on the fall velocity of fog droplets.
 

Similar threads

  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 4 ·
Replies
4
Views
4K
Replies
13
Views
6K
Replies
14
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K
Replies
9
Views
4K
Replies
2
Views
9K
Replies
10
Views
4K
  • · Replies 5 ·
Replies
5
Views
4K
  • · Replies 1 ·
Replies
1
Views
2K