question a street light is at the top of a pole that has a height of 17 ft. a woman 5 ft tall walks away…

question a street light is at the top of a pole that has a height of 17 ft. a woman 5 ft tall walks away from the pole with a speed of 8 ft/s along a straight path. how fast is the tip of her shadow moving away from the pole when she is 18 ft from the base of the pole? (leave your answer as an exact number.) provide your answer below: her shadow is moving at ft/s

question a street light is at the top of a pole that has a height of 17 ft. a woman 5 ft tall walks away from the pole with a speed of 8 ft/s along a straight path. how fast is the tip of her shadow moving away from the pole when she is 18 ft from the base of the pole? (leave your answer as an exact number.) provide your answer below: her shadow is moving at ft/s

Answer

Explanation:

Step1: Set up similar - triangles

Let $x$ be the distance of the woman from the base of the pole and $y$ be the distance from the base of the pole to the tip of her shadow. By similar triangles, we have $\frac{17}{y}=\frac{5}{y - x}$. Cross - multiplying gives $17(y - x)=5y$. Expanding, $17y-17x = 5y$, and then $12y=17x$, so $y=\frac{17}{12}x$.

Step2: Differentiate with respect to time

Differentiate both sides of $y=\frac{17}{12}x$ with respect to time $t$. Using the chain rule, $\frac{dy}{dt}=\frac{17}{12}\frac{dx}{dt}$.

Step3: Substitute the given value of $\frac{dx}{dt}$

We know that $\frac{dx}{dt}=8$ ft/s. Substituting this into the equation $\frac{dy}{dt}=\frac{17}{12}\frac{dx}{dt}$, we get $\frac{dy}{dt}=\frac{17}{12}\times8=\frac{34}{3}$ ft/s.

Answer:

$\frac{34}{3}$