Finding train stopping distance from inclined pendulum angle

  • Thread starter Thread starter captainjack2000
  • Start date Start date
  • Tags Tags
    Inclined Pendulum
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
1 reply · 2K views
captainjack2000
Messages
96
Reaction score
0

Homework Statement


A train is traveling at 30m/s and decelerates and stops. During this process a passenger notices that a penduum is inclined by 10 degrees to the vertical. Estimate how far the train travels before coming to rest


Homework Equations





The Attempt at a Solution


I have drawn a diagram of the pendulum hanging from a string with tension T at an incline of 10 degrees to the vertical. The tension will have two components
Ty=Tcos(10)=mg and
Tx=Tsin(10)=ma
Tx will be the net horizontal force on the pendulum

rearranging I got tan(10)=a/g

then using v^2=u^2+2as
s=(v^2-u^2)/2a
=(0-30^2)/2gtan(10)=260.415m which seems a big too large
 
Physics news on Phys.org
I haven't checked your numbers, but your method looks fine. (And 260m doesn't seem like too large a stopping distance for a TRAIN to me:smile:)