# Velocity and Distance

ViewtifulBeau
2 trains have the speed 44.3 km/h, are headed each other on the same straight track. A bird that flies 177.2 km/h flies from the front of one train when they are 132.9 km apart and heads directly other train. On reaching the other train it flies directly back to the first train, and so forth.

what is the total distance the bird travels?

So i figure that I have to use pythagorian theorem. One of the legs is 132.9km but I don't know how to find the other leg. Thanks.

Homework Helper
Gold Member
There are no triangles involved here, so Pythagoras isn't necessary.

There's a hard way and an easy way to do this problem. I'll let you think about it some more.

ViewtifulBeau
Crap, ok i disreguarded the "same" straight track. Ok so the are going head to head! But is there an equation to find the time when two objects are approaching each other? I don't know many equations, we haven't gone over any in class.

ViewtifulBeau
ok i thought i figured it out at 170.1km, but it says that is wrong. What did i do wrong?

First we want to find the time the two trains will collide. So $$\frac{132.9 km}{44.3 \frac{km}{h}+ 44.3\frac{km}{h}} = \frac{3}{2} [/itex] hours. So multiply the eagles speed by this. Remember distance divided by velocity gives you time according to [tex] d = rt$$