Question

A ladder of 15ft. long leans against a smooth vertical wall. If the top slides downwards at the rate of 2ft sec. Find how fast the lower and is moving when the lower end is 12ft. from the wall.

Answer 1

Given \(\frac{dy}{dt}\)= 2ft /sec, x = 12 

From fig, x² + y² = 15² 

12² + y² = 15² 

y² = 15² – 12²