[Nikyma]

A woman was being chased by a gang of bandits. She had escaped with two solid gold balls, and the bandits wanted to kkill her and take the balls. She came to a wooden bridge over a deep ravine. The bridge was 100 feet long. There was a sign on the bridge that said "Maximum weight on this bridge is 112 pounds." This notice was 100% accurate--the bridge would break if it carried more than 112 pounds. She weighed 100 pounds and each of the balls weighed 10 pounds. There was no time to leave one ball and come back for it later. And yet she managed to escape across the bridge to safety with both balls. How could this be?

[Brandonb]

she bowled them across, or dropped 8lbs of clothing.

[Guest]

since she weighed 100 pounds, she might be a shot put player and she threw the 2 balls or atleast 1 to the other side of the bridge

[Guest]

Juggled, though that does not truely work when you have to use force to throw or you gain force catching, best to rollem or bowlem

Got to be a joke in that OP somewhere - but I'll play safe!

[Nikyma]

Got to be a joke in that OP somewhere - but I'll play safe!

Juggled, though that does not truely work when you have to use force to throw or you gain force catching, best to rollem or bowlem

Safety first - yes that was the answer I have.

[Guest]

Safety first - yes that was the answer I have.

It is saf to say that David Beckham was and maybe still called

Golden Balls!

[Nikyma]

It is saf to say that David Beckham was and maybe still called

Golden Balls!

That's gotta hurt!

[Guest]

He was famous for his dead balls (free kicks - Engalnd football/soccer cpt)

[Guest]

She juggled them while she ran across the bridge. That way one was always in the air and did not count as part of the 112 lb weight limit.

[bonanova]

juggling doesn't work.

Spoiler for why not?:

simple physics - if the weight of the woman and her *ahem* balls is not supported by the bridge, she/they will fall into the ravine.

Better just to throw one across.

[itachi-san]

juggling doesn't work.

Spoiler for why not?:

simple physics - if the weight of the woman and her *ahem* balls is not supported by the bridge, she/they will fall into the ravine.

Better just to throw one across.

I don't get why it doesn't work. She would only be holding one ball at a time. The 2 lb. leeway (112 - 110) should account for the extra momentum of 1 ball falling at a time.

[bonanova]

I don't get why it doesn't work. She would only be holding one ball at a time. The 2 lb. leeway (112 - 110) should account for the extra momentum of 1 ball falling at a time.

When the ball in the air falls into her hand, a force greater than the weight of the ball must be exerted: first, to bring the ball to rest [remember f=ma?] and then to accelerate it upward again. If she were simply to hold it, the force would only be its weight.

Take a running jump onto a bathroom scale [carefully] and you'll see it register a higher "weight" as you land.

[Guest]

kinetic nergy

[Guest]

A woman was being chased by a gang of bandits. She had escaped with two solid gold balls, and the bandits wanted to kkill her and take the balls. She came to a wooden bridge over a deep ravine. The bridge was 100 feet long. There was a sign on the bridge that said "Maximum weight on this bridge is 112 pounds." This notice was 100% accurate--the bridge would break if it carried more than 112 pounds. She weighed 100 pounds and each of the balls weighed 10 pounds. There was no time to leave one ball and come back for it later. And yet she managed to escape across the bridge to safety with both balls. How could this be?

because I read this one in the same book as your other two. she juggled them.

[Guest]

I really like the lateral thinking of juggling the balls, but it wouldn't work. First of all I don't know many 100 lb (wo)men who could juggle two 10 lb balls for a 100ft walk. Secondly, each time she catches the ball, her total mass would exceed the weight limit.

I like the whole "get a running start and jump onto your scale" idea, but that's a little dangerous especially in the bathroom. Just squat a little on a scale, then stand up. You'll see your weight bounce up a bit. Or even better, stand on a scale, toss a 10 pound object in the air and then catch it. You'd need quite a bit more than 2 pounds of leeway for that to work.

Not all bridges are level, if she got lucky and this bridge sloped down towards the other side, then she could just set the ball down, give it a push, and wait until it got to the other side to cross the bridge.

She just took the bridge next to it that had a higher weight capacity.

[itachi-san]

When the ball in the air falls into her hand, a force greater than the weight of the ball must be exerted: first, to bring the ball to rest [remember f=ma?] and then to accelerate it upward again. If she were simply to hold it, the force would only be its weight.

Take a running jump onto a bathroom scale [carefully] and you'll see it register a higher "weight" as you land.

That's why I noted that there is a 2 lb difference between the woman with one ball and the weight limit of the bridge. I think that she can keep the weight created by the force of the fall under 2 lbs, thus she would never exceed the weight limit of 112 lbs.

[bonanova]

That's why I noted that there is a 2 lb difference between the woman with one ball and the weight limit of the bridge. I think that she can keep the weight created by the force of the fall under 2 lbs, thus she would never exceed the weight limit of 112 lbs.

It goes back to my first answer: the total weight of the system comprising the woman and two balls is 120 lbs.

If that entire system attempts to cross the bridge together, it will fall into the chasm unless the bridge keeps it from falling.

To do that, the bridge must exert an upward force [on average during the crossing] of 120 lbs.

So says Sir Isaac Newton.

So if there is ever a moment when the exerted upward force is less than 120 lbs, [a ball is in the air]

there must be another moment when it's greater than 120 lbs - the average must be 120.

And if at any moment it exceeds 112 lbs, the bridge will fail.

So the entire system cannot cross at once.

But, 100 feet is not that far.

Throw one of the balls across the chasm; then carry the other one across.

There are other analogies.

Soldiers break cadence when marching across bridges to keep their instantaneous weight within the capacity of the bridge.

Bouncing up and down in an elevator by a near-limit group of passengers can create a memorable result.

And so on.

The weight that needs to be supported can be reduced momentarily, but only at the price of increasing it later on.

[Guest]

lol, this has changed from a riddle to debate about the laws of physics and mathematics

[bonanova]

lol, this has changed from a riddle to debate about the laws of physics and mathematics

Not really.

The OP is a physics problem pure and simple.

OK I'll meet you half-way. It's a physics riddle.

[Guest]

The woman throws one ball or both of the balls across the bridge and she crosses the bridge safely.

[Guest]

She could just roll them.. 100 feet is only 1/3 of a football field.

and 8lb. gold balls would have a good kenetic energy.. they would make it.

unless you roll really weakly