Is the train an inertial reference frame if luggage starts sliding forward?

In summary, the conversation discusses the concept of an inertial reference frame and how it applies to a train that is slowing down. It is concluded that the train is not an inertial reference frame because the piece of luggage starts moving, indicating a change in its speed and direction. The conversation also explores examples of acceleration and its effects on objects within a moving vehicle.
  • #1
physicsgurl12
184
0

Homework Statement



You are in a train traveling on a horizontal track and notice that a iece of luggage starts to slide toward the front of the train. from this observation you can conclude that this train is not an inertial reference frame because it is slowing down.

Homework Equations



true

The Attempt at a Solution

its true but why??
 
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  • #2
Uhh... what's the definition of an inertial reference frame?
 
  • #3
a FRAME REFERANCE THAT DESCRIBES TIME AND SPACE
 
  • #4
it has no acceleration
and for the crate to move there must be deacceleration
 
  • #5
Hmm, let's take a look at wikipedia.
It says (skipping a couple of paragraphs):

"In an inertial frame, Newton's first law (the law of inertia) is satisfied: Any free motion has a constant magnitude and direction"

Does the piece of luggage have a motion with constant magnitude and direction?


physicsgurl12 said:
it has no acceleration
and for the crate to move there must be deacceleration

Turning this around: if the train deaccelerates, the crate would move.
What if the train accelerates?
 
  • #6
if the train accelerates it would stay still
 
  • #7
physicsgurl12 said:
if the train accelerates it would stay still

Have you ever been standing in a train or bus that accelerates?
If you have, did you have trouble to keep standing?

Or in a car, can you feel it if the car accelerates?
 
  • #8
um it was a while algo, but is it like when it takes off it acclerates so you kinda jerk forward?
 
  • #9
Well, if a train accelerates, you are jerked forward.
And if you don't compensate you'll be flying to the back of the train.

In a car you are pressed against the back of the seat.
And when a car is braked, you'd fly forward except that the safety belts keep you in place.
 
  • #10
okay so for the luggage to slide forward you must be accelerating
 
  • #11
Well... a piece of luggage would not try to compensate...
 
  • #12
so it would just slide back then
 
  • #13
Yes - if the train were accelerating, the piece of luggage would slide back.

What was the question again?
 
  • #14
why can you conclude it is not an initial referance frame?
 
  • #15
physicsgurl12 said:
why can you conclude it is not an initial referance frame?

Not exactly...

The question starts by stating that the piece of luggage starts moving forward.
... and it ends with the question whether the train is slowing down.

Does it?
 
  • #16
yes.because its the opposite of it moving forwards
 
  • #17
Right! :smile:

As for the inertial reference frame question:

Does the piece of luggage have a motion with constant magnitude and direction?
 
  • #18
yeah?
 
  • #19
Well, it's rather important that the piece of luggage "starts" moving.
That means that its speed (or motion) is *not* constant...
 

FAQ: Is the train an inertial reference frame if luggage starts sliding forward?

What is a train inertial reference frame?

A train inertial reference frame is a coordinate system that is fixed to a train and moves with it, allowing for the measurement of motion and forces relative to the train's movement. It is used to understand the train's motion and to make calculations and predictions about its movement.

How is a train inertial reference frame different from other reference frames?

A train inertial reference frame differs from other reference frames, such as the Earth's reference frame, in that it is constantly moving and accelerating along with the train. This means that objects on the train will appear to be at rest in this frame, even though they may be moving relative to objects outside of the train.

Why is a train inertial reference frame important in scientific research?

A train inertial reference frame is important in scientific research because it allows for the accurate measurement of motion and forces on a moving train. This is crucial in fields such as physics and engineering, where understanding the effects of motion and forces is essential in the design and operation of trains and other vehicles.

How is a train inertial reference frame established?

A train inertial reference frame is established by using a set of coordinate axes that are fixed to the train and move with it. These axes are oriented in a way that is convenient for the specific experiment or study being conducted, and they allow for the measurement of motion and forces along different directions.

Can a train inertial reference frame be used for other types of transportation, such as airplanes?

Yes, a train inertial reference frame can also be used for other types of transportation, such as airplanes. In fact, any vehicle or object that is in motion can have its own inertial reference frame. However, the specific axes and orientation of the frame may vary depending on the type of transportation and the specific experiment or study being conducted.

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