Physics problem help!?

[thebest]

Not really an IB physics problem, but a physics 11 problem regardless... I don't understand how this question makes sense. :/ A detailed and thorough (long) explanation would be good!

"An interesting and practical feature of the Montreal subway system is that, in some cases, the level of the station is higher than the level of the adjacent tunnel. Explain the advantages of this design. Take into consideration such concepts as FORCE, ACCELERATION, WORK, POTENTIAL ENERGY, AND KINETIC ENERGY.

And there is a picture showing this train going up a hill, but im really not sure if the train is going down or up the hill since thers no direction on it.... Help.

[Héctor Melara]

Hi, if the station is higher than the tunnel, the train at point A has high potential energy. At point B, the train starts to lose the potential energy and gains kinetic energy. I can't give you the whole answer, because the point of the assignment is that you UNDERSTAND the concept. I think that from there you can continue

[thebest]

Hi, if the station is higher than the tunnel, the train at point A has high potential energy. At point B, the train starts to lose the potential energy and gains kinetic energy. I can't give you the whole answer, because the point of the assignment is that you UNDERSTAND the concept. I think that from there you can continue

Yep, but I don't get what the difference between the energies (whether it be kinetic or gravitational) and the work is. S:

So the conservation of energy from high potential to kinetic energy results in greater velocity over time as the train goes down the hill right? And since the velocity is increasing (not constant), it has a constant acceleration which is what is increasing the speed.

But how would you relate force and work into this?... Sigh

[Drake Glau]

FORCE, ACCELERATION, WORK, POTENTIAL ENERGY, AND KINETIC ENERGY

E_k=0.5mv²

a=v/t

f=ma

w=fd

You should find all your understanding in those equations

More potential energy to start and then converting yields a high kinetic energy that is gradually increasing. Since the mass is essentially remaining constant then the velocity must be increasing.

But like I said the kinetic energy is gradually increasing which means the velocity is gradually increasing and since a=v/t this gradual increase in velocity is creating an acceleration.

The force comes from newton's 2nd law which basically states f=ma, again mass is constant, so as the acceleration increases the force is increasing.

The work comes from the force and distance the train travels. Both increase as the train moves so the amount of work much be increasing also.

So with some thinking, the train being just a little higher provides gravitational (potential) energy if you want to call it that and assuming a constant mass for the entire process the train itself does not need to put out its own energy to travel the same distance at the same speed.