Hannah's car used of a tank of gas to
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Answer:
36
Step-by-step explanation:
We have to compute 4 distances and then add them up.
It may help to draw this first to see which distances to compute.
So I'm going to start with computing the distance from (0,0) to (5,12), then from (5,12) to (9,9), then from (9,9) to (12,5), and then finally from (12,5) to (0,0).
So distance from (0,0) to (5,12)
d=sqrt((5-0)^2+(12-0)^2)=sqrt(25+144)=sqrt(169)=13
Distance from (5,12) to (9,9)
d=sqrt((9-5)^2+(12-9)^2)=sqrt(4^2+3^2)=sqrt(16+9)=sqrt(25)=5
Distance from (9,9) to (12,5)
d=sqrt((12-9)^2+(9-5)^2)=sqrt(3^2+4^2)=sqrt(9+16)=sqrt(25)=5
Distance from (12,5) to (0,0)
d=sqrt((12-0)^2+(5-0)^2)=sqrt(12^2+5^2)=sqrt(144+25)=sqrt(169)=13.
Up all of our distances 13+5+5+13=(13+13)+(5+5)=26+10=36
Answer:
Step-by-step explanation:
This is a typical problem of u.a.r.m. ( uniformly accelerated rectilinear motion). Let's take an eye on the u.a.r.m. equations:
We know the runner started from rest so we can discard as
Also we can consider she starts at .
All we have to do now is replace these values at our equations to obtain:
As we are told that the acceleration remains constant, we can then find the time it took for her to run the whole distance as follows:
First we note that the ratio between her velocity and the time it takes for her to run a certain distance is constant. This is:
In particular, if we take where
is the total time it takes for her to run the whole distance
We know that at this point the velocity is:
So that:
Now we can replace this in the equation of motion
Where we finally find that