A. 216 B. 108 C. 72 D. 48
2 answers:
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Answer:
0.44 ft/sec.
Step-by-step explanation:
Let A is the bottom of the ladder and AB is the distance from the bottom of the wall i.e. B is the bottom of the wall. If C is the top of the ladder and BC is the height of the wall.
Now, Δ ABC is a right triangle and AC is the length of the ladder i.e. hypotenuse.
Now, AC² = AB² + BC² {From Pythagoras Theorem}
Now, differentiating both sides with respect to time t, we get
⇒
Now, given that feet/sec.
Hence, ......... (1)
Now, given that AB = 9 ft. and AC = 15 ft.
So, 15² = 9² + BC²
⇒ BC² = 144
⇒ BC = 12 feet.
Now, from equation (1), we get
Therefore, the bottom of the ladder is sliding away from the wall at the rate of 0.44 ft/sec. (Answer)