can a swing be pushed hard, so it will go all the way around?

Question

if i push aa swing very hard, will it go all the way around?? plz a scientific answer

Answer 1

Theoretically yes. If a hot wheels car can complete the loop the loop on the hot wheels track, then you can certainly have enough kinetic energy to for the swing to to go all the way around.

In practice, it's going to be virtually impossible for a person to do.

At the top of the swing, the centripetal acceleration will have to be equal to or greater than the acceleration due to gravity. Centripetal acceleration is equal to:

a(c)=v^2/r

Gravitational attraction is equal to: g (9.8 m/sec^2)

With a 2 meter chain, the swing will have to be travelling at about 4.43 meters/sec.

The swing loses kinetic energy as it gains potential energy:

mgh(final) - mgh(initial) + 1/2mv^2(final) - 1/2mv^2(initial) =0

If the initial position is the bottom of the swing and considered to be zero and final position is above the swing, then h = 2r. The final kinetic energy (top of the swing) is at least 1/2m(4.43 m/sec). That means that:

m(9.8 m/sec^2)(4 m) + 1/2m(19.6 m^2/sec^2) - 1/2mv^2(initial) = 0
39.2 m^2/sec^2 + 9.8 m^2/sec^2 = 1/2 v^2(initial)
100 m^2/sec^2 = v^2(initial)
10 m/sec = v(initial)

If the swing started horizontal, a potential energy of m(9.8)(2) is converted to 1/2mv^2, or
19.6 m^2/sec^2 = 1/2 v^2
39.2 m^2/sec^2 = v^2
6.26 m/sec = v

Your push is going to have to accelerate the swing from 6.26 m/sec to 10 m/sec. If the swing is travelling 6.26 m/sec, it has an angular velocity of 3.13 rad/sec, or about 180 degrees per second. If the swing is travelling at 10 m/sec, it has an angular velocity of 5 rad/sec, or about 286 degrees per second.

Obviously, you have less than a third of a second to acclerate from 6.26 m/sec to 10 m/sec. Given maybe .333 sec at best, the rate of acceleration will be 11.22 m/sec^2. For a 30kg child, this will require a force of 336 N, or about 76 pounds of force.

76 pounds of force wouldn't be a lot of force to apply to a stationary object. Applying that kind of force to an object that's rotating 180 degrees per second is going to be extremely hard, since a lot of effort is going to go into just keeping up with the swing's speed. The faster you get the swing going, the harder it is to keep your arms moving fast enough to accelerate it further.

Myth busters is entertainment. You know they could just solve a lot of these myths mathematically, but what would be the fun in that. In spite of a very flawed process, they do eventually provide some real information, but ....... The episode about whether cell phones or static electricity from getting in and out of the car while fueling the car were responsible for gas station fires was particularly lame - they couldn't look up the required air to fuel mixture for gasoline to combust prior to the several failed attempts at starting a simulated gas station fire? Sometimes, I think they do dumb things just to build suspense over the conclusion.

Answer 2

Absolutely...go to your neighborhood playground. We used to do it all the time so that the chain would wrap around the top pole and make the seats higher from the ground. Keep in mind that...is just pushing the swing itself. If someone was in the swing it would take a tremendous amount of force...one heck of a push. But if enough force was put into pushing that swing that momentum energy has to go somewhere! The chains hold the swing into a revolution pattern. So until the momentum energy is used up the swing will continue to circle the top pole.

Answer 3

No.

This was done on mythbusters and what they found the leading reason to disprove this idea was the chain holding the swing.

They were only able to do this when there was no chain but instead a solid bar that holds the swing. Even with that, they needed mini rockets to thrust it hard enough to loop. They simulated this on a small scale but I think that when converted, it was way more energy needed than a person could actually push.

Answer 4

Of course it can. Since the chain, or rope, holding the seat to the top of the swing frame will keep the seat from leaving the frame the only possible action would be for the swing to continue in a centrifugal motion to continue until completely wrapped around the frame. This, of course, is contingent upon the direction of the force being such that it promotes this effect. QED (Quod Erat Demonstrandum (Latin: Which Was to Be Demonstrated)).

Answer 5

They tried this on Mythbusters and it took a few rockets to get the swing to go all the way around. A very hard push by several people was able to get it nearly vertical but it was not a complete loop.

Answer 6

Nope. They did this on "Myth Busters" and the myth was busted. They explained it well . . . can't remember why. But it can't be done.

Discovery Channel :: Mythbusters: Episode Guide
... from the schoolyard. If you push hard enough, can you get a swing to go all the way around the swing-set bar? Everyone's tried this ...


url: dsc.discovery.com/fansites/mythbusters/episode/00to49/episode_04.html...
date: August 18, 2004

Answer 7

Yes.

In order for the swing to flip over the highest point, its rotational kinetic energy has to be larger than the gravitational energy at its highest point.

For a swing hanging from rigid rods of length R, we can calculate the speed v0 needed:

1/2 m v0^2 = 2 m g R
v0^2 = 4 g R
v0 = 2 sqrt(g R)

Suppose your swing hangs from 1.50 m (5 ft) rods, then you need to push it to 7.7 m/s = 27.6 km/h (17 mph) and it will flip over its highest point.

Answer 8

Of course it will. If someone is in it, you would need to push really hard. If you are in the seat, you can't do it unless it's a stiff rod instead of a chain.

The only science you need to add is that you can impart enough force to push such a light weight around the pole?

Answer 9

if you can can push it hard enough, yeah it'll go all the way around.
if the swing is long you'll have to push much harder because the swings has to cover more distance to go all the way around

Answer 10

No. They proved it on Mythbusters. They had to strap a rocket behind Buster the dummy to get it to go all the way around.