Answer:
7.142m/s
Step-by-step explanation:
Velocity=change is distance/change in time
change in distance=400m-0m=400m
change in time=56-0=56seconds
v=400m/56s
v=7.143m/s
Multiplying both sides by
gives

so that substituting
and hence
gives the linear ODE,

Now multiply both sides by
to get

so that the left side condenses into the derivative of a product.
![\dfrac{\mathrm d}{\mathrm dx}[x^3v]=3x^2](https://tex.z-dn.net/?f=%5Cdfrac%7B%5Cmathrm%20d%7D%7B%5Cmathrm%20dx%7D%5Bx%5E3v%5D%3D3x%5E2)
Integrate both sides, then solve for
, then for
:




![\boxed{y=\sqrt[3]{1+\dfrac C{x^3}}}](https://tex.z-dn.net/?f=%5Cboxed%7By%3D%5Csqrt%5B3%5D%7B1%2B%5Cdfrac%20C%7Bx%5E3%7D%7D%7D)
First, set these expressions equal in an equation. solve for x, then multiply x by 3 because there are 3 sides. the perimeter is 12
Answer:
3 x 21
20 x 4 tenths
21 x thirteenth
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