NIELIT 2016 MAR Scientist C - Section B: 17

Question

A ladder $13$ feet long rests against the side of a house. The bottom of the ladder slides away from the house at a rate of $0.5$ ft/s. How fast is the top of the ladder sliding down the wall when the bottom of the ladder is $5$ feet from the house?

• A. $\dfrac{5}{24} \text{ ft/s} \\$
• B. $\dfrac{5}{12} \text{ ft/s} \\$
• C. $-\dfrac{5}{24} \text {ft/s} \\$
• D. $-\dfrac{5}{12} \text{ ft/s}$

Answer 1

Ans:C

Hint: Differentiation is used.