A little physics brain teaser to drive you crazy.

[Random Variable]

If an object moving along at some constant velocity is subjected to a frictional force that is proportional to the velocity of the object, the object will slow down and come to a stop.

On the other hand, if the same object is subjected to a frictional force that is proportional to the square of the velocity of the object, the object will slow down more rapidly but it will never come to a stop.

Why?

 

[KLin]

Boys have a penis, girls have a vagina.

 

[jordanz]

Originally posted by: KLin
Boys have a penis, girls have a vagina.

LOL

 

[Random Variable]

Originally posted by: KLin
Boys have a penis, girls have a vagina.

some have both

 

[TheLonelyPhoenix]

Originally posted by: KLin
Boys have a penis, girls have a vagina.

orly?

 

[orakle]

Link? Proof? I'm interested.

Edit: In the physics stuff.

 

[Howard]

Originally posted by: Random Variable
If an object moving along at some constant velocity is subjected to a frictional force that is proportional to the velocity of that object, the object will slow down and come to a stop.

On the other hand, if the same object is subjected to a frictional force that is proportional to the square of the velocity of the object, the object will slow down more rapidly but it will never come to a stop.

Why?

Force proportional to velocity means that there will be negative acceleration until velocity becomes 0.

Still thinking about the second part.

 

[Random Variable]

Originally posted by: orakle
Link? Proof? I'm interested.

Edit: In the physics stuff.

In the first case mdv/dt=-cv; in the second case mdv/dt=-cv^2. For each case integrate twice to find functions for position and notice that the limit as t->infinity in the first case is a finite number while in the second case it's infinity.

 

[Mardeth]

Am I totally out of the loop if I say its because: 0.9^2 = 0.81, 0.5^2 = 0.25, 0.01^2=0,0001 etc..... as it slows down the frictional force gets smaller, it will slow down forever but never totally stop.

 

[Random Variable]

Originally posted by: Mardeth
Am I totally out of the loop if I say its because: 0.9^2 = 0.81, 0.5^2 = 0.25, 0.01^2=0,0001 etc..... as it slows down the frictional force gets smaller, it will slow down forever but never totally stop.

No, that's basically the reason. Good job.

 

[jagec]

Naw, this is a .99999... != 1 problem. The object WILL eventually come to a stop, if only because eventually, the speed will become quantized.

 

[Soccerman06]

Originally posted by: jagec
Naw, this is a .99999... != 1 problem. The object WILL eventually come to a stop, if only because eventually, the speed will become quantized.

Ya this is simple calculus, as a # gets smaller, it will eventually reach 0, even if its 1/x. It may not be a real number, but its still there and is called a limit.

 

[Random Variable]

Originally posted by: jagec
Naw, this is a .99999... != 1 problem. The object WILL eventually come to a stop, if only because eventually, the speed will become quantized.

I sorts see where you're coming from, but you're wrong.

 

[Trevelyan]

Originally posted by: Soccerman06

Originally posted by: jagec
Naw, this is a .99999... != 1 problem. The object WILL eventually come to a stop, if only because eventually, the speed will become quantized.

Ya this is simple calculus, as a # gets smaller, it will eventually reach 0, even if its 1/x. It may not be a real number, but its still there and is called a limit.

Exactly... the velocity -> 0 as t-> infinity

 

[Random Variable]

Originally posted by: Trevelyan

Originally posted by: Soccerman06

Originally posted by: jagec
Naw, this is a .99999... != 1 problem. The object WILL eventually come to a stop, if only because eventually, the speed will become quantized.

Ya this is simple calculus, as a # gets smaller, it will eventually reach 0, even if its 1/x. It may not be a real number, but its still there and is called a limit.

Exactly... the velocity -> 0 as t-> infinity

but x->infinity as t->infinity

 

[dighn]

are you sure about the first case? even if f = cv, numerically the velocity doesn't become 0 for a finite interval

edit: I see you really mean the position as t -> inf

 

[chuckywang]

Cause the frictional force will decrease more rapidly when velocity < 1, since square of a number less than is lrss than that number.

 

[Iron Addict]

If first sentence is true then second one has to be false.
If first sentence is false then second one has to be true.

Concept of proportionality in which applied between friction and velocity does not change whether the proportionality is based on 1st, 2nd or infinite power of the value of origin.

 

[Cerpin Taxt]

There's no fvckin' way that plane is gonna take off.

 

[fuzzybabybunny]

You need to first cool it with solution.

 

[SophalotJack]

Originally posted by: KLin
Boys have a penis, girls have a vagina.

It's NOT a tumor!

 

[Zolty]

Originally posted by: TheLonelyPhoenix

Originally posted by: KLin
Boys have a penis, girls have a vagina.

orly?

hawt

 

[imported_Trippin315]

This thread was more interesting when they were talking about the people with both parts.

 

[Born2bwire]

Originally posted by: Random Variable

Originally posted by: Trevelyan

Originally posted by: Soccerman06

Originally posted by: jagec
Naw, this is a .99999... != 1 problem. The object WILL eventually come to a stop, if only because eventually, the speed will become quantized.

Ya this is simple calculus, as a # gets smaller, it will eventually reach 0, even if its 1/x. It may not be a real number, but its still there and is called a limit.

Exactly... the velocity -> 0 as t-> infinity

but x->infinity as t->infinity

Yeah so? Velocity still comes to a halt in the same way it did in the first case.

 

[Fenixgoon]

AND I HAVE A PHYSICS PROBLEM FOR YOU!

if a plane is on a conveyor belt style runway, and the rate at which the surface of the belt moves is always equal to the velocity of the airplane, will the plane ever take off?