A train is moving at 15 m/s
A woman is swinging from a pendulum that is 12m long.
They will both intersect at position X

How long before the train reaches position x will the woman have to jump in order to land on it.
Give answer in time and distance


Help please!

me thinks we need a picture

^^^
definitely more info needed
like:
what is the position of the pendulum in regard to the train tracks
what is the angle to the train track the pendulum swings
how tall is the woman
how long is the train

The top of the pendulum is directly overhead the train tracks
it will swing directly across the tracks.
No angle given
Assume height is 0 i guess
Assume heigh is 0 again

if it's all zero it would be at x and it dies not seem to be the required answer
so as 'Azrad' stated, it needs a picture

here are the problems I see off the top of my head:

• jumping adds a new force, perhaps you mean "when should the woman let go of the pendulum?"
• we need to know the height of the pendulum at rest (or at some other point), and the height of the train
• what does "land on the train" mean, is it a "point train" where she has to hit the exact point of the train, or is there like a platform so there will be a range of times she can make it?
• are we assuming it is a small angle of swing (isochronous)?

The following assumes:
idealized pendulum with isochronous swing
"point train"
pendulum (at rest) and the train happen to be at the same height
woman will let go when the pendulum "delivers" her to the train.


T is how long it takes to go from a starting "high point" (only potential energy), to move through the low point (all kinetic), to the "opposite" high point (all potential).
The women is planning on letting go at the bottom then you want 1/2*T. So the train needs to be 1/2*T seconds away. You have the trains velocity so calculating the distance shouldn't be hard.