Perpetual motion in a hammock

June 6, 2009 9:29 PM

How do you keep yourself in perpetual motion in a hammock?

I just got my first hammock. It's the quilted kind, with spreader bars, and it's hung between two trees in my yard. It's great. I love the gentle swinging. However, once I'm lying in the middle of the hammock, the swinging eventually comes to an end. I'm at a loss of how to get swinging again without actually putting a foot out and giving myself a push. Any pointers? Are there special wiggle manoeuvres or something that will keep me perpetually in motion without getting out? Thanks

posted by crazycanuck to grab bag (11 comments total)

Just move your hips side to side.
posted by sanka at 9:31 PM on June 6

rope tied (hopefully) to third tree, or maybe to a branch of the 2 trees, or else to a peg in the ground. You have to pull on the rope to keep swinging, but you do continue to swing.
posted by kch at 9:35 PM on June 6 [3 favorites]

Only nine bucks for this thing.
posted by Conrad Cornelius o'Donald o'Dell at 10:05 PM on June 6 [2 favorites]

It's not quite the classic perpetual motion machine, because you can
still do work against your own body. For example, a child on a swing set
can come down to vertical and then continue through to someplace higher
than where he started. He does this by keeping his legs extended coming
down and tucking them in as he goes up, so that his moment of inertia is
less and the fixed angular momentum he builds on the way down carries
him farther up. That's not a violation of thermodynamics because he's
still doing work against the force gravity on his legs.

A purely analogous solution to the hammock would involve flexing your
back to lie more or less bent (center of mass lower or higher, and
moment of inertia larger or smaller, respectively) in the hammock. That
sounds uncomfortable. Shifting your hips sounds like a good idea.
posted by d. z. wang at 10:17 PM on June 6

Like sanka said. I usually have a limb hanging over the edge which I can wave to keep the hammock moving. It's like pumping a swing.

Though TBH I've never minded having the hammock settle down while I'm lying in it.

It's been years since I've had a hammock. I wonder if I can put one up in my small yard.
posted by hattifattener at 10:19 PM on June 6

Pay my kid five bucks to swing me. Ten if he doesn't talk.
posted by pearlybob at 10:29 PM on June 6 [5 favorites]

Wow, third rope? Buying gadgets?

I wiggle my ass a little. After a while you doze off, so you don't notice the rocking anymore.
posted by paisley henosis at 10:47 PM on June 6 [1 favorite]

The less you think about it, the more okay you'll be.
posted by hpliferaft at 11:44 PM on June 6

Find a smooth tree branch, roughly 4-ft long and 1-2 inches in diameter, with a wide Y bifurcation on one or both ends. Lean on the side of the hammock with the forked end on the ground. You've made a push pole.
posted by zennie at 7:37 AM on June 7

Put the crate of beer just slightly out of reach. Seriously.
posted by dowcrag at 9:17 AM on June 7 [1 favorite]

Yeah wiggling my hips wasn't doing it for me. $9 for a pulley sounds like a good deal. My kid does like to push but she isn't big enough for bribery.
posted by crazycanuck at 10:25 AM on June 7