Login    Register
User Information
Username:
Password:
We are a free and open
community, all are welcome.
Click here to Register
Sponsored
Who is online

In total there are 56 users online :: 3 registered, 0 hidden and 53 guests


Most users ever online was 155 on Mon Aug 15, 2016 1:40 am

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot] based on users active over the past 5 minutes

The Team
Administrators
Global Moderators
global_moderators.png CS

A basic slingshot question

All non-spudgun related discussion goes here such as projects, theories, serious questions, etc. All "off-topic" posts (aka useless posting, determined by moderators) will be removed.
Sponsored 
  • Author
    Message

A basic slingshot question

Unread postAuthor: boyntonstu » Sat Aug 15, 2009 12:17 pm

A basic slingshot question

Question:

Assume that prior to drawing back the pouch, it is 10" from the fork.

You pull it back 20" to 30" from the fork.

Would the speed of the projectile be the same if it is released from the pouch at 10" as it would if it was released after it passed the fork?

BoyntonStu
  • 0

User avatar
boyntonstu
Brigadier General
Brigadier General
 
Posts: 1039
Joined: Sun Jun 28, 2009 8:59 am
Reputation: 0

Unread postAuthor: jrrdw » Sat Aug 15, 2009 1:26 pm

You have to figure in friction of moving through dead air, the rate of acceleration to the point where the acceleration stops and the dead air really starts affecting the "ball bearing" for reference. Off the top of my head...
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Re: A basic slingshot question

Unread postAuthor: Ragnarok » Sat Aug 15, 2009 1:30 pm

Unless I'm being an idiot, for practical purposes, the two are essentially the same.
  • 0

Does that thing kinda look like a big cat to you?
User avatar
Ragnarok
Chief of Staff
Chief of Staff
 
Posts: 5339
Joined: Tue Dec 19, 2006 8:23 am
Location: The UK
Reputation: 8

Re: A basic slingshot question

Unread postAuthor: jrrdw » Sat Aug 15, 2009 1:46 pm

Ragnarok wrote:Unless I'm being an idiot, for practical purposes, the two are essentially the same.


Explain please, witch two?
  • 0

When life gives you lemons...throw them back they suck!
User avatar
jrrdw
Donating Moderator
Donating Moderator
 
Posts: 6538
Joined: Wed Nov 16, 2005 5:11 pm
Location: Maryland
Country: United States (us)
Reputation: 25

Unread postAuthor: jimmy101 » Sat Aug 15, 2009 1:52 pm

I would say that the release 10" before the fork would be prefered. This assumes the drag on the cables and pouch is greater than the drag on the projectile. Both the cable/pouch and the projectile start to decelerate at the 10" mark (the equilibrium lenght of the slingshot). The cable/pouch probably has a higher Cd and lower sectional density than the ammo so it will decelerate faster than the ammo. If the ammo is still connected to the pouch then the pouch will decelerate the ammo more than the ammo decelerates itself.
  • 0

Image

jimmy101
Lieutenant General
Lieutenant General
 
Posts: 3128
Joined: Wed Mar 28, 2007 9:48 am
Location: Greenwood, Indiana
Country: United States (us)
Reputation: 7

Re: A basic slingshot question

Unread postAuthor: D_Hall » Sat Aug 15, 2009 1:55 pm

boyntonstu wrote:Would the speed of the projectile be the same if it is released from the pouch at 10" as it would if it was released after it passed the fork?

It will be FASTER at the 10" mark than it will be after it passes the fork. Not much faster, but faster. Why? Because once the rubber makes it to it's unstretched length (the 10" mark), you've accelerated the projectile as much as you're going to. After that, it's decelerating all the way.

And truthfully, it will probably be at it's fastest ever so slightly before the 10" mark. For at the 10" mark the acceleration force from the rubber is zero while drag is non-zero. Peak velocity will be just before that... At the last moment when acceleration force due to the rubber exceeds drag forces.
  • 0

Simulation geek (GGDT / HGDT) and designer of Vera.
User avatar
D_Hall
Donating Member
Donating Member
 
Posts: 1759
Joined: Thu Feb 07, 2008 7:37 pm
Location: SoCal
Reputation: 6

Return to Non-Spudgun Related Discussion

Who is online

Registered users: Bing [Bot], Google [Bot], Yahoo [Bot]

Reputation System ©'