How far did the train travel before stopping after detaching a compartment?

Join the discussion
Registration is free. Start your own thread to ask a follow-up.
3 replies · 4K views
mrhobbes
Messages
3
Reaction score
0
A train moving up an incline at 4 degrees has it's last train compartment detached. The train was moving at a speed of 5 m/s when the compartment breaks free. How far did the train get before the speed momentarily reaches zero?

No other information is given, but using all that was provided, I got a ridiculously small answer of 0.09 m. I got this by splitting up my speed into x and y components and then using the Vo(y) in the equation d= vf² - vo² / 2a to get my vertical displacement. I then used distance to get my inclined displacement by using sin 5 = y / r.

I checked the answer and it turns out that it was wrong. Could anyone give me any hints on how to solve the problem?

Thanks
 
Physics news on Phys.org
Welcome to PF.
The question doesn't make much sense as written. Perhaps it means a train CAR breaks free from the back of the train. Without engine. How far does the CAR go up the hill?

It's initial speed is 5 m/s. Since it is going up the hill, its KE will soon be converted into PE. You could begin with
initial KE = final PE
.5*mv² = mgh
and quickly find the height reached from the initial position. You'll have to convert that into a (larger) distance along the ramp with a bit of trigonometry. I'm getting a little more than 18 m.