Riddles ... isn't it.

Forbiddenbiker

Forbiddenbiker

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Adam
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If you’re travelling at 60 mph and you crash into a solid unmoving wall… how come the speed of your faces impact with the closest surface is 260 mph?

A plane is sitting on a mile long conveyor belt and has to reach 100mph before it can take off… The belt will move at the same speed as the plane, but in the opposite direction… will the plane take off?

If time and space don’t really exist, why is it I managed to have two crashes today …one in a van this morning and another on a bike this afternoon…

..and whay even after this .... do I think I’m such a good rider and competent driver often pondering about going rallying or racing around Donnington Park on my lavy……. when plainly I’ve crashed way too many time for one person in one life time, I’ve seriously lost count let alone the actual memory.

…now that really is a riddle.

Blinking left none right, looking no, quick turning, flipping cage drivers ‘U’ turners. …I curse yous.

I’m absolute fine btw. ...answers anyone? :)

…hows your day been? :D
 
i bet you is going to hurt in the morning
 
Forbiddenbiker said:
A plane is sitting on a mile long conveyor belt and has to reach 100mph before it can take off… The belt will move at the same speed as the plane, but in the opposite direction… will the plane take off?
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yes because a planes acceleration is not dependant on groundspeed due to the force moving it being provided to the air around it and not to the wheels in contact with the ground (compared to a car whice would remain stationary at 100mph on a rolling road.), therefore while the ground may be moving at the same speed in the oposite direction for the plane to travel at 100mph its wheels would actually be rotating at 200mph to overcome the 100mph of the wheels and the 100mph forwards movement of the plane. therefore as long as the plane reaches 100mph in the given mile the plane should still be able to takeoff as long as the turbulence created by the conveyor belt does not prevent it......


ive got a feeling theres something stupid about the question and im gonna end up looking like a fool:bonk:
 
whitewash said:
I’ve got a feeling there’s something stupid about the question and im gonna end up looking like a fool:bonk:
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:D No, spot on mate...:thumbs: I think. :thinking: I was just going to say the engines push the air and are attached to the wings...the wheels have nothing to do with it... so it will still take off as normal. :D

But your explanation will do. :D


I'm sooo flipping bored today...ordered parts for the first crash, did the insurance stuff...seen my boy, crashed again :bang:

....nothing else to do ... and sort of anxious kinda feeling from missing work today, and the rest of the week. I'm self employed so who know how can feel eh....the monies not an issue as I will claim it all back in time.... just a pain eh.

Just been fixing the bike with gaffer tape and cable ties....quality bodger me. :thumbs: :D ... Off for a cuppa in a bit round a mates house.

---

First riddle yet anyone?
 
A plane is sitting on a mile long conveyor belt and has to reach 100mph before it can take off… The belt will move at the same speed as the plane, but in the opposite direction… will the plane take off?
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This one question went to about 20 pages on a forum I do cleaning for. Some people just couldn't accept the concept of an airplanes propulsion. :lol:

Nice to see it dealt with so swiflty. :clap:
 
oops yes it can, it's not driven by it's wheels but by the jet engines... silly me.
 
Steep said:
If the belt moves at the same speed as the plane (no matter what speed), the plane will have no forward motion, if it has no forward motion it has no airflow over it's wings and cannot take off.
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Please. Tell me you are not being serious?
 
E-slapped by Bob Monkhouse, the shame! :)
 
:lol: .... the peeps on this forum are just to bright... :( ;)

--
I'll give you a clue for the first one.. It is a bit of a naughty/daft one.

Years ago...before technology filled our cars...The same crash in the same circumstances, would have meant your faces impact would have been 60mph ...as you'd expect.

Got it now? :naughty:

...don't hate me. :D
 
Forbiddenbiker said:
: ... and sort of anxious kinda feeling from missing work today, and the rest of the week. I'm self employed so who know how can feel eh....
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Over a year now since my business closed down. Got the final sign off from the liquidator a couple of weeks ago. That feeling you describe is something I don't miss at all :)
 
Forbiddenbiker said:
If you’re travelling at 60 mph and you crash into a solid unmoving wall… how come the speed of your faces impact with the closest surface is 260 mph?
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I am not where the 260mph comes from but thought it would be 120mph based on the fact that each force has the equivalent opposing force and the 2 are added together hence 120mph but my physics was cr*p so could be completely wrong, which aacounts for the fact I took Biology :lol:
 
nuffink said:
I am not where the 260mph comes from but thought it would be 120mph based on the fact that each force has the equivalent opposing force and the 2 are added together hence 120mph but my physics was cr*p so could be completely wrong, which aacounts for the fact I took Biology :lol:
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See posts above - its cos of the force of you hitting the airbag.
 
Joe, it's not moving compared to the conveyer belt but it is moving compared to the ground (that's where I made my mistake). Because the wheels are not driven they can spin as fast as they like and have no effect on the motion of the aircraft, it's the same as if the aircraft is in the air.
 
Joe T said:
Doesnt the plane need 100mph of airflow over its wings in order to generate lift? If it is not moving compared to the ground, it will be not moving compared to the air around it? :thinking:
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The best way to cut through the physics in this one is to state theirs nothing holding the plane back... theirs thrust so theirs push on the air, and an opposite push on the wings, but theirs no chain holding the plane. The wheels will travel twice as fast as normal; the belt will spin away like crazy trying to match the speed of the plane which IS taking off.
 
nuffink said:
I am not where the 260mph comes from but thought it would be 120mph based on the fact that each force has the equivalent opposing force and the 2 are added together hence 120mph but my physics was cr*p so could be completely wrong, which aacounts for the fact I took Biology :lol:
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surely your nose would still hit the dash at 60mph without an airbag (i presume forbiddenbiker has researched that the airbag will be traveling forwards at 200mph)the car would stop almost instantaniously (disregarding any crushing of components etc disipating any energy) and everything not fixed to the car (such as an unbelted passenger would continue to move forwards at 60mph and commence decelerating before hitting anything solid.....



the force with which your face hits the dash can be worked out through the equation force = mass*acceleration, but thats not whats being asked...
 
Speed of the airbag has nothing to do with what speed your head hits the dash. If the airbag deploys then in theory your head shouldn't hit the dash at all.

If it does hit the dash, then the airbag obviously didn't deploy correctly and so the 260mph is irrelevant :p
 
Nuff, WW. It’s simply the speed of each moving item combined to give the total speed at the moment of impact. ...

I didn't want to complicate the riddle with seat belts, they don't really come into it anyway....I should have mentioned it was a car though WW. :)

...
Hey :lol: ..don't you just love physics. :geek: ;) Another... :D

I wrote this a few years ago …..

WW.. your not allowed to answer this…please, cos I know you will guess right.

Imagine this….it is real..

Question. what am I?

An arc of lightening crosses the void detonating the atmosphere’s molecules and burning hotter than the sun. The atmosphere containing mainly atomized hydrocarbons, nitrogen and oxygen ignites. This explosive flame rushes down a tube and meets a sealed solid wall travelling at 300 mph in the opposite direction which compresses the burning mixture. As this wall reaches its peak of travel upwards the mixture reaches a its fully burning state, the resulting extreme pressure wave now accelerates the wall downwards again and a machine prepares for another revolution out of 300 its going to do in that single second at 14000 rpm.

:nuts: :D
 
Has anyone take friction into account? And what about the maximum speed that the tires can spin at before exploding? Was plane was on the travelator going backwards at 100mph before thrusting engines?

I really don't think this question has been given full consideration before being dismissed as nonsense.
 
ranarama said:
Has anyone take friction into account? And what about the maximum speed that the tires can spin at before exploding? Was plane was on the travelator going backwards at 100mph before thrusting engines?

I really don't think this question has been given full consideration before being dismissed as nonsense.
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Depends on how the question is phrased and how far you want to take the physics with it.

If the treadmill 'speed matches' the wheels, then, in theory the wheels and belt would soon reach an infinite speed and it would be a case of whether the bearings in the planes wheels melted before the conveyor. If the wheels melted then the plane would likely get suddenly thrown backwards and end up as a mangled heap. If the conveyor broke first, then assuming the wheels of the plane were ok it would probably take off.

Of course, if you ignore the problem of friction entirely and assume the belt and wheels are quite content going at whatever speed, then the plane will take off due the fact it is powered by jets thrusting air not wheels pushing along the floor.

Obviously much more could be said on many aspects but at the end of the day the only 'right' answer is "it depends"
 
I really hate to be the one to say this, as I'm not normally quite so fed up, but why do people even entertain these kind of threads?

I shall probably end up regretting saying that.. but for the mo... :bang:
 
Woodsy2k said:
I really hate to be the one to say this, as I'm not normally quite so fed up, but why do people even entertain these kind of threads?

I shall probably end up regretting saying that.. but for the mo... :bang:
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Yep, hopefully. ...yah kill joy you... Its not our fault you don't understand. :lol:

...keep it to yourself ya misery, cos we don't give a damn ::razz:


Chuckurbarla said:
A cylinder of an internal combustion engine on the combustion stroke.
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:thumbs: You got it. ...I should have left off the 14000 revs bit eh....gives it away. ;)
 
Yes the rpm was a bit of a giveaway, coupled with the fact that I was heavily involved with that sort of thing for a good while. Nice description of it though :)

By the way Woodsy, sorry you're so fed up, anything we can do to help?
 
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