HELP PLEASE... s the front of a train going going the same speed as the back???

Question

My seems to think that a train is going faster in the front than it is going at the end.... and he even thinks that if you had 10 cars on the express way in a line ,and the front is doing 70 , the next one can only do 69, then next can only do 68 all the way down to car 10 can only do 60 ...would someone tell him all ten can do 70 together...PLEASE

Answer 1

Macroscopically yes.
Microscopically it can be said that when the train is accelerating the front starts moving faster than the back (slightly).
This distinction is one of the fundamentals of relativity.

Answer 2

Your question seems to be about a caravan of cars on a highway, not a (railroad) train.

In the steady state, all the cars travel at exactly the same speed. If the second car does only 69.9, it will gradually drift back and increase its distance from the leader. If they maintain constant spacing, each will cover 70 miles in the same amount of time.

Answer 3

To begin, lets define our terms more specifically.

Speed is scalar. Scalars are quantities with only magnitude. The direction does not matter. If you are on the highway whether traveling 100 km/h south or 100 km/h north, your speed is still 100 km/h. Other examples of scalar quantities are shoe size, mass, area, energy.

(average speed) = (total distance)÷(total time)

The speed of an object is how much its position changes in a given amount of time. As long as we can measure a position and a time, we can define a speed.

The speed of an object is always measured "relative to" the speed of something else (hence the term "relativity"). For instance, if I sit at a railroad crossing and watch a train go by, I might measure the speed of the train as 50 miles per hour. On the other hand, if I'm in a car moving alongside the train at 45 miles per hour then the speed of the train will only appear to me to be 5 miles per hour. (When you get near the speed of light things start to behave a little differently but that's another story, Einstein's "special" relativity). The point is that we always measure speed with respect to some particular frame of reference.

So, as a fixed observer each car would appear to travel at the same speed (zero accerlation).

If you want another puzzeler, would a person walking accross a really wide train travel at the same speed from one side to the other!

Dr. H

Answer 4

No, each car goes the exact same speed.

Otherwise, the trains wouldn't stay together.

Think about it this way: what if the train was just one really long car: obviously the whole car is moving at the same speed, right? (I mean, the front bumper of your automobile doesn't move any faster than the rear bumper, right?) Well, even though you have multiple cars, they are all attached, so the train is effectively one big "thing".