# Simple conceptual reference frame question

• Rubberduck2005

#### Rubberduck2005

Homework Statement
If a train is moving at some constant V with a bed sitting still on top. When the train decelerates at some rate -A then the bed will move at some acceleration A. I can't seem to get an intuition for how this comes to be. I have looked online and find no help.
Relevant Equations
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If a train is moving at some constant V with a bed sitting still on top. When the train decelerates at some rate -A then the bed will move at some acceleration A. I can't seem to get an intuition for how this comes to be. I have looked online and find no help.

Seems pretty straightforward.

If you're sitting on top of the train, what do you see the (wheeled) bed do ?

If a train is moving at some constant V with a bed sitting still on top. When the train decelerates at some rate -A then the bed will move at some acceleration A.
One assumes that you are learning about "frames of reference".

When you say that the train is decelerating, you should further qualify that statement. What is that deceleration relative to? Probably you mean that the deceleration is relative to an inertial frame in which the track is at rest.

When you say that the bed is accelerating, you should further qualify that statement. What is that acceleration relative to? Probably you mean that the deceleration is relative to an accelerating frame of reference in which the train is at rest.

The bed seems to be accelerating because the coordinate system you are measuring its acceleration against is itself accelerating.