# Momentum question. Acceleration on a moving track

Tags:
1. Feb 14, 2016

### Berts

Hi,

I've a question that is baffling me a little.

If a train was made so that it would act as a moving track / roadway and the cars were connected so as to complete a length of the track, in an oval for example. Say we accelerate the moving trackway to 100 Mph, and then a car accelerates to 100mph. Total speed = 200mph.

Now say you have a moving track on top of the railway track. Are all of the speeds combined, is it even possible? Would I imagine it would be like running on a travelator? So long as you joined the train at 100mph would you instantly accelerate to 200 mph?
It is hurting my brain and I know something in my thinking is incorrect!

2. Feb 14, 2016

### A.T.

How did that "instantly" come into this?

3. Feb 14, 2016

### Berts

Ah yes I see now,

But once on the train you could then accelerate the vehicle and go 200mph....

4. Feb 14, 2016

### Staff: Mentor

I assume you mean something like this: Say a train is moving at 100 mph East with respect to the ground/track. And you, on the train, are riding a motorcycle at 100 mph East with respect to the train. (Pretend it's a long flat bed train.) Then your speed with respect to the ground will be 200 mph.

Is that what you mean?

5. Feb 14, 2016

### Berts

Yes thanks :-)