# The Naked Scientists Forum

### Author Topic: Rain falls with uniform velocity in my frame and accelerates in yours?  (Read 5333 times)

#### Anukshan Ghosh

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• Posts: 15
##### Rain falls with uniform velocity in my frame and accelerates in yours?
« on: 18/01/2011 07:21:57 »
Lets assume rain falls with a velocity of 3m/s in my frame.Now if you in your bike approaching me face to face at a uniform velocity of 4m/s ,the rain falls at 5m/s in your frame and that too inclined at 53 degrees from the vertical unlike in my frame.
The answer might be pretty easy if you just say it as pseudo force but nature cannot be so unruly and if it knows when to throw n pseudo force and when to not.

#### CliffordK

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##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #1 on: 18/01/2011 08:29:30 »
Is it accelerating?  Or just going at a different velocity with respect to the frame of reference?

Would riding a bicycle be any different from riding an elevator upwards?

#### Anukshan Ghosh

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• Posts: 15
##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #2 on: 20/01/2011 08:20:47 »
Even I know that on changing the frame the velocity of the rain drop changes its too prominent to miss, but you didn't answer why it changes on changing a frame of reference.Does it accelerate while changing frames within the dimensions?

#### CliffordK

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##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #3 on: 20/01/2011 09:42:00 »
If you have 3 trains, all passing each other.

A:  travelling east to west at 50 mph.
B:  travelling west to east at 50 mph.
C:  travelling west to east at 100 mph.

When A looks at C, he sees C travelling at 150 mph from west to east.
When B looks at C, he sees C travelling at 50 mph from west to east.
When B looks at A, he sees A travelling at 100 mph from east to west.
When C looks at A, he sees A travelling at 150 mph from east to west.
When A looks at B, he sees B travelling at 100 mph from west to east.
When C looks at B, he sees B travelling at 50 mph from EAST TO WEST.

Each person sees the other trains going at different directions.
In fact, B appears to reverse directions depending on whether you are observing it from A or C.

But, there is no acceleration (except when the trains initially left the station).

#### Anukshan Ghosh

• Jr. Member
• Posts: 15
##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #4 on: 20/01/2011 12:10:08 »
In my example θ with the vertical changed with respect to frames also velocities changed from 3 to 5.If I claim that there are frames in which you can find the same rain drop falling with 3.00001,3.00002,3.00004................3.0009,4.0001....................4.00099 and 4.99999999...5 then it could only mean that the rain drop is accelerating through frames, now my doubt should be crystal clear to you.

#### Anukshan Ghosh

• Jr. Member
• Posts: 15
##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #5 on: 24/02/2011 06:48:24 »
Actually what happens is that due to the disturbance, that is me in the system,I experiences the frequency of the raindrops increase or rate of falling ,in simplest terms, increase.

#### Bored chemist

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##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #6 on: 24/02/2011 19:30:40 »
"Does it accelerate while changing frames within the dimensions?"
The two frames of reference are people moving with different velocities. To move from one of those frames to the other you would have to change velocity. It is you that accelerates.

Incidentally, I am a raindrop and all of us raindrops seem stationary to me.

#### Anukshan Ghosh

• Jr. Member
• Posts: 15
##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #7 on: 11/03/2011 08:05:45 »
yup it surely does but my question is centered around the rain and the two men in the universe

#### JMLCarter

• Sr. Member
• Posts: 143
##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #8 on: 11/04/2011 23:59:50 »
The point is that the raindrop does not change at all.

Observer A (stationary) sees the rain fall straight down, including, say, a particular raindrop that I shall, for want of a better name, call Bored chemist.

Observer B (on his bike moving towards A) sees the same rain completely unchanged but because he is moving forwards the rain appears to move towards him.

Observer A and B can both look at exactly the same raindrop, Bored chemist, at exactly the same time and both observe a different velocity relative to them. The raindrop does not change. Is it accelerating? No it is not.

Also note that in A's frame of reference B is travelling towards him, but B has not hoped on a bike.

« Last Edit: 12/04/2011 00:02:52 by JMLCarter »

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##### Rain falls with uniform velocity in my frame and accelerates in yours?
« Reply #8 on: 11/04/2011 23:59:50 »