Question

A ladder 5 m long is leaning against a wall. The bottom of the ladder is pulled
along the ground, away from the wall, at the rate of 2cm/s. How fast is its height
on the wall decreasing when the foot of the ladder is 4 m away from the wall ?

Answer 1

@Leaper

Answer 2

rate means change with respect to time. So you're going to be taking some derivatives.
Let x be the dist of foot of the ladder from the wall and y the height of the point of contact between the ladder and the wall.
At any instant when the ladder is falling down, the length of the ladder is const=5m. (it forms a triangle, hence you'll be using pythagorean). so \(x^2+y^2 = 5^2\)
take the derivative of the function and plug in 2 cm/ s in for ur "x" since you already know most of ur inforamtion you have "x" and "y"

It might help to draw a diagram

Answer 3

ok

Answer 4

label ur information

Answer 5

Thankyou Sir