Struggling with this problem....

[MartinQ]

This all too much for me, you lot'll break the internet if you're not careful.

Sorry about bringing some logic ....

 

[Fab Foodie]

For those interested (and some good thinking has been shown), the answer can be found here:

https://www.bbc.co.uk/programmes/articles/4VvcGv74FRMjxDGdZrMV7Z0/today-puzzle-756

 

[Fab Foodie]

Sorry about bringing some logic ....

Uncommon about these parts....

 

[Deleted member 26715]

For those interested (and some good thinking has been shown), the answer can be found here:

https://www.bbc.co.uk/programmes/articles/4VvcGv74FRMjxDGdZrMV7Z0/today-puzzle-756

Whoop whoop I was right, maybe for the wrong reasons but I don't care,

 

[MichaelW2]

My gut reaction is that it makes no difference as all momentum transfer is internal to the egg timer.

A thought experiment to explore:

Imagine a very light, very tall cylinder, say Nelson's column size but near zero mass and containing a perfect vacuum. The cylinder has a cannonball at its base, and is instantaneously upended, and placed on a weigh scale. What would the scales observe?

I think:

1. Initially, just the weight of the cylinder. No force exists between cannonball and cylinder, so it's existence cannot be detected by the weigh scale.
2. A very high spike as the cannonball hits the base, transferring momentum. Much more than the weight of the cannonball itself.
3. A constant weight equal to the cylinder plus cannonball.

So I change my gut reaction and propose that the weight does, indeed, reduce by the weight of the sand in flight.

Now replace the cannonball with a very heavy feather...

 

[SpokeyDokey]

This reminds me of the budgie flying around in an aircraft question.

A good few years ago I jokingly convinced a work colleague that the more information he downloaded onto his hard disk, the heavier his computer would be.

I was surprised to find the answer when I googled it.

Tease.

 

[Salty seadog]

My instinct is to say it would weigh less.

I'm now going to open the link to the answer.

 

[Salty seadog]

My instinct is to say it would weigh less.

I'm now going to open the link to the answer.

Bugger!

 

[Rocky]

For those interested (and some good thinking has been shown), the answer can be found here:

https://www.bbc.co.uk/programmes/articles/4VvcGv74FRMjxDGdZrMV7Z0/today-puzzle-756

I hate to disagree, Fabbers but the link I posted shows it weighs more.

 

[midlife]

Hmm, If there is perfect vacuum in the hourglass and the sand is falling at a a perfectly steady rate with zero friction, then if there is conservation of momentum the weight on the scales should be the same. As the sand starts to fall at the beginning the weight will decrease but increase again a the falling sand hits the bottom of the hourglass if elastic collisions......now my head has exploded !

 

[roubaixtuesday]

I hate to disagree, Fabbers but the link I posted shows it weighs more.

The BBC answer is pants

 

[MartinQ]

Now replace the cannonball with a very heavy feather...

Can I have a swallow carrying the cannon ball?

 

[Deleted member 26715]

Can I have a swallow carrying the cannon ball?

An African Swallow?

 

[Salar]

Can I have a swallow carrying the cannon ball?

I would expect all body functions are acceptable.

 

[MartinQ]

An African Swallow?

Maybe a European carrying the holy hand grenade of Antioch.