Riddles with a Prize, by Mantus Anchors - Page 7 - SailNet Community
Vendor

Join Date: Dec 2011
Posts: 184
Thanks: 7
Thanked 1 Time in 1 Post
Rep Power: 5

Re: Riddles with a Prize, by Mantus Anchors

The Jack in the Box
Jack weighs m
Box weighs M

So if you depress the head of the Jack and release it suddenly, it will pop up because of the spring between the Jack and the bottom of the box. How much force is required to depress the Jack so that both the Jack and the Box will jump up into the air? The mass of the Jack is m and the mass of the Box is M and the weight of the spring is negligible.
The spring is regular linear spring....

The PRIZE is MANTUS CHAIN HOOK that fits your chain size....
Attached Thumbnails

Anchor Purveyor
Mantus Anchors is offline

Old 11-20-2012
░░░░░░░░░░

Join Date: Apr 2006
Posts: 12,185
Thanks: 6
Thanked 170 Times in 167 Posts
Rep Power: 12

Re: Riddles with a Prize, by Mantus Anchors

If I recall my phsyics you are requiring or ignoring any number of unbounded assumptions about the nature of the spring itself. So with your unspoken indication that unbounded assumptions are the key to the answer, I can firmly state that no amount of force will ever be sufficient to make the box pop up into the air, as both the box and Jack are hovering in a zero-gravity LaGrange point in earth-lunar orbit. Without an operational gravity field being specified, any force "down" on the spring will simply repel the entire box, Jack and all, away from the pusher, out of the LaGrange point, and eventually to a violent death as it falls into a gravity well and plunges into the surface below, or bursts into flames en route.
hellosailor is offline
Old 11-20-2012
Junior Member

Join Date: Jun 2012
Location: Gulf Coast
Posts: 11
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 0

Re: Riddles with a Prize, by Mantus Anchors

Quote:
Originally Posted by Mantus Anchors View Post
How much force is required to depress the Jack so that both the Jack and the Box will jump up into the air?
This Force will get Jack into the air...

altho...it might excite him instead of "depress"-ing him - is that allowed?
Attached Thumbnails

red.sky is offline
Vendor

Join Date: Dec 2011
Posts: 184
Thanks: 7
Thanked 1 Time in 1 Post
Rep Power: 5

Re: Riddles with a Prize, by Mantus Anchors

Quote:
Originally Posted by hellosailor View Post
If I recall my phsyics you are requiring or ignoring any number of unbounded assumptions about the nature of the spring itself. So with your unspoken indication that unbounded assumptions are the key to the answer, I can firmly state that no amount of force will ever be sufficient to make the box pop up into the air, as both the box and Jack are hovering in a zero-gravity LaGrange point in earth-lunar orbit. Without an operational gravity field being specified, any force "down" on the spring will simply repel the entire box, Jack and all, away from the pusher, out of the LaGrange point, and eventually to a violent death as it falls into a gravity well and plunges into the surface below, or bursts into flames en route.

I like this answer... but If the Box is made by Mantus it will land safely and survive re-entry...
No there is a solution to this problem... that can be expressed in M and m
Greg

Anchor Purveyor
Mantus Anchors is offline
Old 11-20-2012
Senior Member

Join Date: Apr 2011
Location: Oriental NC
Posts: 297
Thanks: 93
Thanked 19 Times in 13 Posts
Rep Power: 6

Re: Riddles with a Prize, by Mantus Anchors

I can confirm that Greg ships his anchor in one tough box!
bristol299bob is offline
Old 11-20-2012
Senior Member

Join Date: Oct 2009
Location: Gloucester, MA
Posts: 586
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8

Re: Riddles with a Prize, by Mantus Anchors

m+2M
klem is offline
Vendor

Join Date: Dec 2011
Posts: 184
Thanks: 7
Thanked 1 Time in 1 Post
Rep Power: 5

Re: Riddles with a Prize, by Mantus Anchors

not yet...

Anchor Purveyor
Mantus Anchors is offline
Old 11-20-2012
Senior Member

Join Date: Jul 2009
Posts: 110
Thanks: 0
Thanked 3 Times in 2 Posts
Rep Power: 8

Re: Riddles with a Prize, by Mantus Anchors

(m+M)/32
UncleJim is offline
Old 11-20-2012
Senior Member

Join Date: Oct 2009
Location: Gloucester, MA
Posts: 586
Thanks: 0
Thanked 0 Times in 0 Posts
Rep Power: 8

Re: Riddles with a Prize, by Mantus Anchors

m+M
klem is offline
Old 11-21-2012
Senior Member

Join Date: Oct 2011
Location: Nanaimo B.C.
Posts: 3,316
Thanks: 3
Thanked 90 Times in 89 Posts
Rep Power: 6

Re: Riddles with a Prize, by Mantus Anchors

The ratio of m/M .the acceleration of head and box are the inverse. but I don't know Jack.and to lift the box needs enough force to overcome grav. so the force must be M x9.8 meters per sec squared
Capt Len is offline

 Tags anchors , mantus

Message:
Options

By choosing to post the reply above you agree to the rules you agreed to when joining Sailnet.

## Register Now

In order to be able to post messages on the SailNet Community forums, you must first register.
Please note: After entering 3 characters a list of Usernames already in use will appear and the list will disappear once a valid Username is entered.

User Name:
OR

## Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.

 Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)