"A   ladder 5 m long is leaning against a wall. The bottom of the ladder is pulled   along the
Channel: Doubtnut
Date: 2020-07-05

"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 2 cm/s. How fast is its   height on the wall decreasing when the foot of the ladder is 4 m away from   the wall?"