How far do acorns drift in the wind?

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Homework Help Overview

The discussion revolves around estimating how far acorns drift in the wind, with a focus on the effects of wind speed and direction on their movement. The problem is set in a context of creative thinking without explicit instructions, and participants are exploring various assumptions and factors that may influence the outcome.

Discussion Character

  • Exploratory, Assumption checking, Mathematical reasoning

Approaches and Questions Raised

  • Participants discuss the need to assume wind speed and direction, with one noting a specific wind speed of 25 m/s. There are considerations about the natural behavior of acorns and their reliance on animals for transportation. Some participants question the assumptions made regarding air resistance and the relevant equations needed to analyze the problem.

Discussion Status

The discussion is ongoing, with participants encouraged to share their attempts and relevant equations. Some have provided initial calculations related to time of fall and forces acting on the acorns, while others suggest comparing terminal velocity with wind velocity. There is no explicit consensus on the approach, but there is a focus on ensuring that participants articulate their reasoning and calculations.

Contextual Notes

Participants are working under the constraint of limited information and the requirement to demonstrate their thought processes and attempts at solving the problem. The discussion includes assumptions about air resistance and the need for relevant equations to be stated clearly.

nick-metersecondsq
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New user has been reminded to please always show their work on schoolwork problems.
Homework Statement
we live under a lot of trees, including great oaks. How far can wind carry a falling acorn?

acorn mass: 4.5g
acorn size and shape: r=3cm (assuming sphere)
height of fall: 27m
air density 1.225 kg/m3
Relevant Equations
this is open
this one is our extra credit problem with no instructions. just creative thinking.
 
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It seems you would need to assume a wind speed and direction.
 
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Acorns rely on ground transportation (mostly squirrels and chipmunks).
When they drop, they generally stay within the trees immediate shade/shed zone.
 
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sorry I left that off. speed is 25 m/s and direction is parallel to the ground.
 
So what attempt have you made to solve the problem yourself? We don't spoon feed answer, but rather help people who are trying to help themselves.
 
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Thread closed for Moderation...
 
Thread is reopened provisionally.

@nick-metersecondsq -- Please show your best efforts to work on this problem so that the thread can remain open. It is important for you to list the Relevant Equations involved.
 
nick-metersecondsq said:
sorry I left that off. speed is 25 m/s and direction is parallel to the ground.
Please post a complete statement of the given problem. There are relevant equations, so please post what you think they might be and tell us why. We need to understand the problem as well as your attempt at solving it.
 
Mister T said:
It seems you would need to assume a wind speed and direction.
berkeman said:
Thread is reopened provisionally.

@nick-metersecondsq -- Please show your best efforts to work on this problem so that the thread can remain open. It is important for you to list the Relevant Equations involved.
so far I know t = √(2h/g gives me time ... so t=sqrt(2(27)/9.8 = 2.35s

Force of wind is F = 0.5 * p * v^2 * A * Cd. i'm assuming drag coeff of 1.2?

F=2.6
mass of wind = density * area = M= 1.229 kg/m3 * (3 pi r2 = .000084*1.229= .00010

I need F=ma, solving for A since I have t and need distance.
but maybe my algebra is wrong, but that gives me A=F/m = 206000 ms2 (which is bonkers).
and that's where I'm lost.
 
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nick-metersecondsq said:
so far I know t = √(2h/g gives me time ... so t=sqrt(2(27)/9.8 = 2.35s
That is with the assumption of zero air resistance.
nick-metersecondsq said:
Force of wind is F = 0.5 * p * v^2 * A * Cd. i'm assuming drag coeff of 1.2?
That is with the assumption of non-zero air resistance.

Maybe you could try computing terminal velocity and compare that with the landing velocity under the assumption of free fall.

Or maybe you could compare terminal velocity with wind velocity.
 

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