The Wonderland Board

He juggles.

Correct. With one video game always in the air, the bridge only had 149.8 pounds to support.

Actually, no, it doesn't. According to Newton's Third Law, every action has a counter-action, an equal force that's directed the opposite way. Basically, if your finger is pressing on a rock, the rock is pressing on your finger.

Therefore, the very act of juggling those videogames causes the juggler to exert a downward force on that bridge.

Had the force been equal to the weight of said games, it would maybe turn out to be possible by starting juggling before going across the bridge and keeping all 3 games in the air. So at any point he'd only have to counteract the weight of ONE game instead of three.

However, he also has to counteract the force of gravity to actually throw said games up. So that combined force is already enough to break the bridge. (And please don't make me calculate this -- it's a hard calculation whilst common sense tells me that even if it's somehow possible, then no real juggler would be able to do everything this perfectly)

In fact, juggling in this case is even worse than not juggling.

"Real" ways to do this:
1) Come back for one of those games later.
2) As long as the bridge is short enough, you could just throw the games across the bridge and then walk over it empty-handed. (:lol:)
3) The bridge doesn't respond directly to the weight. Like any other physical object, it responds to pressure. Said pressure is distributed evenly across the contact area. If you stand on your two legs, the contact area is too small, making for pressure that is too big for this particular point. So lie on your chest and start crawling towards the goal. Given how light those videogames are, it'll probably work.
4) But the safest way is to find another way to Guy's house and ignore the bridge entirely.

Interesting!

I have to agree with Muzozavr: The total gravity forces of the three videogames are always (averagely during the way across the bridge) affecting the force of Guy's feet on the bridge. (There are no other forces to avoid them falling on the ground, then the forces on his body; no need to calculate. )

Also nice alternative solutions. Here are some more:

- He goes to the toilet first to reduce his weight.
- He goes running fast, quite a while for the same reason
- He also carries a big balloon with helium, to reduce his gravity force
- He uses his jacket or a fly-kite against the wind, for the same reason

It doesn't matter as long Joe reaches Guy's house.

Muzozavr wrote:the very act of juggling those videogames causes the juggler to exert a downward force on that bridge.

I disagree. The only downwards force each video game would have on Guy and the bridge would be a normal force of 5.4 ounces. And that's only when Guy is making contact with the video game.

Muzozavr wrote:However, he also has to counteract the force of gravity to actually throw said games up. So that combined force is already enough to break the bridge.

Guy and the video games are not accelerating at all if Guy isn't juggling, therefore you can assume that for each object, the magnitude of their gravitational force would be equal to that of their normal force (5.4 ounces for each video game and 149 pounds for Guy). In order to accelerate a video game upwards to juggle, Guy would have to make his upwards normal force on the video game larger than 5.4 ounces in order to create a net force necessary to launch the video game into the air. When this happens, the downwards normal force on Guy from the video game remains unchanged, therefore throwing the games upwards in order to juggle does not affect anyone's normal force on the bridge.

Regardless, you have to wonder if it's even legal to build a bridge this fragile.

MyNameIsKooky wrote:

Muzozavr wrote:the very act of juggling those videogames causes the juggler to exert a downward force on that bridge.

I disagree. The only downwards force each video game would have on Guy and the bridge would be a normal force of 5.4 ounces. And that's only when Guy is making contact with the video game.

Do you know what's the mass of an Uzi-bullet? I don't, but let's say about 100 to 200 gram, which means their gravity force on Earth is about 1 to 2 Newton .

So, if you lay on your back with such a bullet on your forehead, the force is about 1 to 2 Newton, right?

Now, imagine that I'm standing right in front of you with an Uzi in my hands, pointing at your forehead, what do you think how big the force will be, if I pull the trigger?


*shot*

Here's another hard puzzle

The answer is an answer

Technos72 wrote:Here's another hard puzzle

The answer is an answer

Then I quess the question is a question!

‎

Marinus wrote:

MyNameIsKooky wrote:

Muzozavr wrote:the very act of juggling those videogames causes the juggler to exert a downward force on that bridge.

I disagree. The only downwards force each video game would have on Guy and the bridge would be a normal force of 5.4 ounces. And that's only when Guy is making contact with the video game.

Do you know what's the mass of an Uzi-bullet? I don't, but let's say about 100 to 200 gram, which means their gravity force on Earth is about 1 to 2 Newton .

So, if you lay on your back with such a bullet on your forehead, the force is about 1 to 2 Newton, right?

0.1 to 0.2 Newtons, actually. *murdered*

Marinus wrote:Now, imagine that I'm standing right in front of you with an Uzi in my hands, pointing at your forehead, what do you think how big the force will be, if I pull the trigger?

The gun launches the bullet. After that, the only acceleration is due to gravity, so all of the x forces are balanced. Therefore, the bullet will only apply 0.1 to 0.2 N of force to my forehead.[/completely missing the point]

*shot for real*

Kooky, I must admit that you have a good sense of humor, but if you would like to survive for about 70 years from now on, I think you'd better make an appointment with your physics-teacher, for extra-education (don't know if that's a correct English word, and I'm too lazy to look it up)

OK, here is lesson 1:


Wikipedia says:

1 N is the force of Earth's gravity on a mass of about 100 g = (1⁄9.81 kg).

EDIT:

http://en.wikipedia.org/wiki/Newton_(unit)

I can't get the link working correct right now. I guess I've to add some % ascii code, instead of the underscore _ but I'm too lazy...

MyNameIsKooky wrote:

Muzozavr wrote:the very act of juggling those videogames causes the juggler to exert a downward force on that bridge.

I disagree. The only downwards force each video game would have on Guy and the bridge would be a normal force of 5.4 ounces. And that's only when Guy is making contact with the video game.

No. It's not the video game that puts the pressure on Joe. Try this: stay on the floor with something moderately heavy in your hands (experiment to find the best weight) and then try to raise both hands up very quickly. You'll have to exert upward force for that, right? During that you'll feel how your feet are "pressured" towards the ground for a short time. That's the downward force I'm talking about.

The very act of throwing that videogame up will cause his feet to exert an identical downward force on the bridge.

Emerald141 wrote:An answer.

There, that was easy.

Good. Maybe it's not hard after all

Marinus wrote:I think you'd better make an appointment with your physics-teacher, for extra-education

No, I just started taking physics this year, therefore I don't know what I'm talking about anyways.

Marinus wrote:OK, here is lesson 1:

I was taught that 9.81 N = 1 kg, not 100 g.

MyNameIsKooky wrote:I was taught that 9.81 N = 1 kg, not 100 g.

That is correct. 1 kg = 1000 g

If 1000 g = 9.81 N (almost 10 N) then 100 g = almost 1 N

Oh. I'm an idiot.

MyNameIsKooky wrote:Oh. I'm an idiot.

I wouldn't dare to say that. (But on the other hand I see no reason to disagree with you )

Anyhow, I hope you understand now that the speed of an object affects the forces of impact. If you jump out of an airplane without a parachute, the forces between your body and the Earth are pretty much bigger, then when you're just laying on the beach.

I didn't think about that. Sorry.

LittleZbot wrote:I didn't think about that. Sorry.

Don't worry. It was a nice puzzle anyways!

What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

ALSO

The following equation is wrong: 101 - 102 = 1

Move one numeral to make it correct.

hoomdoom wrote:
ALSO

The following equation is wrong: 101 - 102 = 1

Move one numeral to make it correct.

Already posted that.

101 - 10^2 = 1

Sammy_P wrote:

hoomdoom wrote:
ALSO

The following equation is wrong: 101 - 102 = 1

Move one numeral to make it correct.

Already posted that.

101 - 10^2 = 1

Oh, sorry.

I was sitting staring the 101 - 102 puzzle. I did not know ^ was a numeral, or is it not?

This is an example of what I'm talking about: Move one number to make this problem make sense (yeah it's easy the way I think it)

51 - 110 = 4

hoomdoom wrote:What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

5±9?

MyNameIsKooky wrote:

hoomdoom wrote:What mathematical symbol can be put between 5 and 9, to get a number bigger than 5 and smaller than 9?

5±9?

Nope.

HINT: There are two answers (That I know of)

EDIT: Messed up the math. I know the answer, but I'm not going to say it.

A 4th-root symbol.

MyNameIsKooky wrote:A 4th-root symbol.

That does indeed work, giving the answer of 8.6602540378443864676372317075294. Neat.