Question

16. A ladder 5 metres in length is
resting against vertical wall. The
bottom of the ladder is pulled along
the ground away from the wall at the
rate of 1.5 m/sec. When the foot of
ladder is 4.0 metres away from the
wall, the rate of decrease of the
height on the wall is: *​

Answer 1

Answer:

At any instant x

2

+y

2

=5

2

Differentiating w.r.t. time 2x

dt

dx

+2y

dt

dy

=0

When x=4;y=3

Here

dt

dx

=2,

dt

dy

=u⇒u=

3

8

m/s