Girl injured during ALS bucket challenge

[Aztecfan03]

Wrong. They weigh the same. Other than the pennies being harder, they'll have the same impact. If you put a board in your head and then the bag, they'll be the same. To Darrin, 80 pounds may seem heavy but just think about those acrobats that stand on each other's head. They are more than 80 pounds and the do this with no problem.

Except for the difference in air resistance.

[FkLA]

There's a reason why force is based on acceleration. An object dropped even a short distance has a lot more impact strength than an object placed somewhere.

Downward acceleration of gravity is 9.81 m/s^2 regardless of whether an object is in free-fall or if you are measuring it's weight on a scale.

[FkLA]

https://mtc.cdn.vine.co/r/videos/B80...BgS2EoF7kKyd6y.

^this is the dude who's neck couldve snapped imo, that vid in op has nothing on that one

[cantthinkofanything]

Except for the difference in air resistance.

Read my post closely. A ton of pennies...a ton of feather. It's an old trick question/riddle. People always think of a penny compared to a feather. But the word, "ton" is where the focus should be. A ton of anything is the same weight as a ton of anything else. But my point was that we're only talking about 80kg or whatever.

[Chinook]

Downward acceleration of gravity is 9.81 m/s^2 regardless of whether an object is in free-fall or if you are measuring it's weight on a scale.

Lol. The squared part makes the difference. You know what momentum is, right?

[DarrinS]

Read my post closely. A ton of pennies...a ton of feather. It's an old trick question/riddle. People always think of a penny compared to a feather. But the word, "ton" is where the focus should be. A ton of anything is the same weight as a ton of anything else. But my point was that we're only talking about 80kg or whatever.

80 lbs

80 kg is a little over 175 lbs


But, we're only talking 80 lbs. You should let someone drop 80 lbs on you from 3 feet above your head. I guarantee it would feel different than 80 lbs resting on your head.

[Chinook]

Wrong. They weigh the same. Other than the pennies being harder, they'll have the same impact. If you put a board in your head and then the bag, they'll be the same. To Darrin, 80 pounds may seem heavy but just think about those acrobats that stand on each other's head. They are more than 80 pounds and the do this with no problem.

You're not clever. They weigh the same. But due to air resistance, they have different impact strengths. A feather does not fall as fast as a penny, so it has less momentum.

[FkLA]

Lol. The squared part makes the difference. You know what momentum is, right?

You are not wrong in saying an object dropped would hurt more, it's just not bc of acceleration. If it is not squared then it isn't acceleration.

[FkLA]

You're not clever. They weigh the same. But due to air resistance, they have different impact strengths. A feather does not fall as fast as a penny, so it has less momentum.

If they are both bagged up like he said the air resistance of each object wouldn't matter. You'd have to focus on the bag's resistance...if they're the same size they'd fall at the same speed. Otherwise the smaller bag falls quicker.

[Chinook]

You are not wrong in saying an object dropped would hurt more, it's just not bc of acceleration. If it is not squared then it isn't acceleration.

Yes, it's because acceleration. An object in free fall is under mostly gravitational acceleration, and so it is gaining speed/momentum until it hits the ground/head. An object resting on a surface still has gravitational acceleration, but that's being cancelled by normal force, pushing speed/momentum to zero. That's why a falling object has more impact strength than a stationary one, it takes more force to make it stop.

If they are both bagged up like he said the air resistance of each object wouldn't matter. You'd have to focus on the bag's resistance...if they're the same size they'd fall at the same speed. Otherwise the smaller bag falls quicker.

He said nothing about it being bagged. Even so, objects do fall at different speeds depending on air resistance. Bigger, less dense bags will totally fall more slowly and with less impact force than small, dense bags. Density/size matters; weight/mass doesn't. That is Galileo's principal. A bag with a ton of pennies in it is way smaller than a bag with a ton of feathers.

[cantthinkofanything]

80 lbs

80 kg is a little over 175 lbs


But, we're only talking 80 lbs. You should let someone drop 80 lbs on you from 3 feet above your head. I guarantee it would feel different than 80 lbs resting on your head.

I wouldn't intentionally drop anything on my head. They've done studies that show soccer players having concussions from bouncing the ball of their head and a soccer ball is pretty damn light. The reality is that any sudden head movement can cause concussions (albeit very small unnoticeable ones). But the point I was making was that while a feather is light compared to a penny, a ton of feathers is EXACTLY the same weight as a ton of pennies. Or a ton of gold as the original riddle goes. And in this case 80 pounds of water is the same as 80 pounds of feathers (or gold or pennies). And it's not as neck-snapping, life threatening as people are making it out to be. The mini concussion risk is much higher.

[cantthinkofanything]

If they are both bagged up like he said the air resistance of each object wouldn't matter. You'd have to focus on the bag's resistance...if they're the same size they'd fall at the same speed. Otherwise the smaller bag falls quicker.

Sorry...I should have mentioned that it's all happening in a vacuum.

[FkLA]

Yes, it's because acceleration. An object in free fall is under mostly gravitational acceleration, and so it is gaining speed/momentum until it hits the ground/head. An object resting on a surface still has gravitational acceleration, but that's being cancelled by normal force, pushing speed/momentum to zero. That's why a falling object has more impact strength than a stationary one, it takes more force to make it stop.

The difference in speeds has to do with the potential energy each object has, since it focuses on their respective heights which differ--acceleration doesn't differ.

He said nothing about it being bagged. Even so, objects do fall at different speeds depending on air resistance. Bigger, less dense bags will totally fall more slowly and with less impact force than small, dense bags. Density/size matters; weight/mass doesn't. That is Galileo's principal. A bag with a ton of pennies in it is way smaller than a bag with a ton of feathers.

He said piece of wood and then bag on top of it. Maybe I misunderstood.

Sorry...I should have mentioned that it's all happening in a vacuum.

Then you are right.

[Cry Havoc]

I wouldn't intentionally drop anything on my head. They've done studies that show soccer players having concussions from bouncing the ball of their head and a soccer ball is pretty damn light. The reality is that any sudden head movement can cause concussions (albeit very small unnoticeable ones). But the point I was making was that while a feather is light compared to a penny, a ton of feathers is EXACTLY the same weight as a ton of pennies. Or a ton of gold as the original riddle goes. And in this case 80 pounds of water is the same as 80 pounds of feathers (or gold or pennies). And it's not as neck-snapping, life threatening as people are making it out to be. The mini concussion risk is much higher.

Yeah dude, there's absolutely NO chance of neck or back injuries from that.

[cantthinkofanything]

Yeah dude, there's absolutely NO chance of neck or back injuries from that.

LOL. That pic. She's ducking and as you can see, most of the water is already out.

[Cry Havoc]

LOL. That pic. She's ducking and as you can see, most of the water is already out.

I sincerely hope you're trolling.

[Chinook]

The difference in speeds has to do with the potential energy each object has, since it focuses on their respective heights which differ--acceleration doesn't differ.



He said piece of wood and then bag on top of it. Maybe I misunderstood.



Then you are right.

I don't think we're disagreeing so much as looking at things differently. The fact that gravity is based on acceleration is why height matters so much. The farther something falls, the faster it's going when it hits something. The faster something goes, the more normal force it takes to slow it down in a short distance. That's why nets work for catching jumping people. They increase the distance something can slow down over, and so decrease normal force.

[cantthinkofanything]

That's why nets work for catching jumping people. They increase the distance something can slow down over, and so decrease normal force.

Exactly. Which is also what the neck does.

[FkLA]

I don't think we're disagreeing so much as looking at things differently. The fact that gravity is based on acceleration is why height matters so much. The farther something falls, the faster it's going when it hits something. The faster something goes, the more normal force it takes to slow it down in a short distance. That's why nets work for catching jumping people. They increase the distance something can slow down over, and so decrease normal force.

Yep, I even said you were right about something dropped hurting more. Just stating that it's not necessarily bc of acceleration, bc gravity is constant regardless of height. Although you are right in that the pull of gravity gets things going.

[Chinook]

Exactly. Which is also what the neck does.

Lol. Good one.

[Chinook]

Yep, I even said you were right about something dropped hurting more. Just stating that it's not necessarily bc of acceleration, bc gravity is constant regardless of height. Although you are right in that the pull of gravity gets things going.

Gravity is constant, but the acceleration makes distance important. Like it makes no difference if car that hits you has been driving at 70 MPH for a hour or a second. The impact force is the same. But it makes a huge difference getting hit by a car whose gas pedal has been floored for one half-second rather than two seconds (provided the car was at rest before then).

[FkLA]

Gravity is constant, but the acceleration makes distance important. Like it makes no difference if car that hits you has been driving at 70 MPH for a hour or a second. The impact force is the same. But it makes a huge difference getting hit by a car whose gas pedal has been floored for one half-second rather than two seconds (provided the car was at rest before then).

Sure, the gravity gets it started when in free fall. But an object at rest is hit by that same gravity too. If I were to ask someone to explain the difference, I'd expect energy to be part of the discussion--since height and velocity are so important in determining that difference.

If you just look at both scenarios through Newtons second law, it doesn't tell you much.

[Chinook]

Sure, the gravity gets it started when in free fall. But an object at rest is hit by that same gravity too. If I were to ask someone to explain the difference, I'd expect energy to be part of the discussion--since height and velocity are so important in determining that difference.

If you just look at both scenarios through Newtons second law, it doesn't tell you much.

The first and third laws are the important ones. Something hitting the ground after falling has more normal force acting on it than something resting on the ground.

[FkLA]

There's a reason why force is based on acceleration. An object dropped even a short distance has a lot more impact strength than an object placed somewhere.

You are right. The initial comment^ you made was what was a little off imo. Although upon second look it's not as bad as I thought when I first read it.

No disagreement with what you are saying now.

[HI-FI]

Yeah dude, there's absolutely NO chance of neck or back injuries from that.

i haven't seen the video but that's some exorcist . nasty.