Imagine a railway carriage full of water is moving at constant velocity along an infinitely long,?

Question

Imagine a railway carriage full of water is moving at constant velocity along an infinitely long,
straight, level, frictionless track when it develops a leak and water begins to flow out at a constant
rate, straight downwards. Discuss what will happen to the velocity of carriage as the mass of the
carriage changes. Your answer should refer to Newton’s Laws of Motion as appropriate, and to
the Principles of Conservation of Momentum and Conservation of Energy.

Answer 1

Unless a force is acting in the direction of the train's velocity, no change in velocity will occur. Simply draining water will not affect the velocity of the train. Momentum and Energy are NOT conserved because the mass before and after are different. The train will indeed have less energy and subsequently, less momentum after the water drains, but it will not change velocity as no force is specifically acting in that direction.

Answer 2

In the closest this question gets to 'real life', the water would not flow straight down. It would continue moving in the original direction on the train and retain the momentum it had before the leak.

I suspect the answer the question is looking for is that the railway carriage will increase speed as the momentum of the lost water is transferred to the carriage and the remaining water.

I'm not familiar enough with the details to properly cite the Laws of Motion or Conservation of Momentum or Conservation of Energy.

Answer 3

The question gives you a clue to the answer. They say to use the Laws of motion thing.

The velocity will not change since the water that is coming out (the only thing that is changing) is coming straight out. If the water were coming out either in or against the direction of travel, then you are adding energy to the carraige and the velocity would change.

Answer 4

If the carriage has mass, and I assume it does, this will not change the velocity at all.

Answer 5

Have you ever tried sex as a way to pass the time between quantum physics and Laws of Thermodynamics?

Answer 6

Nothing will change in the situation you've described. The situation you've described is impossible on this earth and the laws you want used wouldn't hold true in space.