Pulse

[zina_6]

a 18 cart train standing on the siding is started in motion by the trains engine.There are 3cm of slack between each car. The cars are 11 m long.The engine is tightly connected to the first car and moves at a constant speed of 25cm/s . How much time is required for the pulse to travel the length of the train ? Answer in units of seconds. :confused:

[Epsilon=One]

a 18 cart train standing on the siding is started in motion by the trains engine.There are 3cm of slack between each car. The cars are 11 m long.The engine is tightly connected to the first car and moves at a constant speed of 25cm/s . How much time is required for the pulse to travel the length of the train ? Answer in units of seconds. :confused:Assuming each cart has no slack; and the rear of the cart moves instantly with the front, without reaction, there are 18 units of 3cm slacks.

The total slack divided by the engine's speed should give the number of seconds required.

As an old brackman that has spent too much time in cabooses and atop freight cars behind steam, electric, and deisel engines, the answer does not appear realistic, and the assumptions are improbable.

[zina_6]

HUM, so the lengths of the cars have no bearing? :(

[Epsilon=One]

HUM, so the lengths of the cars have no bearing? :(Not with my assumptions. And, of course, the type of "pulse" that you are discussing may be other than I have assumed.

[zina_6]

Assuming each cart has no slack; and the rear of the cart moves instantly with the front, without reaction, there are 18 units of 3cm slacks.

The total slack divided by the engine's speed should give the number of seconds required.

As an old brackman that has spent too much time in cabooses and atop freight cars behind steam, electric, and deisel engines, the answer does not appear realistic, and the assumptions are improbable.


Hum, so the lengths of the car has no bearing?

[zina_6]

opps :D i am trying to get accustomed the forum... lol

[HallsofIvy]

No, the lengths of the cars are not important. To any reasonable accuracy, the end of each car starts at the same time as the front!

Probably what is most unrealistic about this problem is that the engine moves with constant speed.

[Talvi Watia]

a 18 cart train standing on the siding is started in motion by the trains engine.There are 3cm of slack between each car. The cars are 11 m long.The engine is tightly connected to the first car and moves at a constant speed of 25cm/s . How much time is required for the pulse to travel the length of the train ? Answer in units of seconds. :confused:

the gradient of 18*3cm/25cm/s = grad ( dx/dt ) * (dv^2)

its a formula of acceleration.

acc = 5cm/s

calculate the weight of the cars and you have work. ( 1/dt^3 )