A bridge is 10 m above a railroad track and at right angles to it. A train is running at the rate of 20 m/s passes under the center of the bridge at the same instant that a car running 15 m/s reaches that point. How rapidly are they separating 3 seconds later?

Question

carlosesgirl · Answer

is there a picture to go with this

jhonyy9 · Answer

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@supie 
@Laylalyssa 
@darknight

any idea how you solve this problem ?

jhonyy9 · Answer

@supie can you pls ask who are good in math problems ? ty

supie · Answer

@darkknight

jhonyy9 · Answer

a little help how you solve it

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jhonyy9 · Answer

any idea now

jhonyy9 · Answer

?

SemiDefinite · Answer

$\vec r_1(t) = [20 t , 0 , 0]$

$\vec r_2(t) = [0 , 15 t , 10]$

$\vec D(t) = \vec r_2 - \vec r_1 $

you want to find $| \vec v|  = \dfrac{ d|\vec D |}{dt} $ when t = 3