Question -
Answer -
Let y m be the height of thewall at which the ladder touches. Also, let the foot of the ladder be x mawayfrom the wall.
Then, byPythagoras theorem, we have:
x2 + y2 = 25 [Length of the ladder = 5 m]
Then, the rate of change of height (y) withrespect to time (t) isgiven by,
It is given that
Now, when x = 4 m, we have:
Hence, the height of theladder on the wall is decreasing at the rate of