No products in the cart.

A ladder 5m long is leaning …

CBSE, JEE, NEET, CUET

CBSE, JEE, NEET, CUET

Question Bank, Mock Tests, Exam Papers

NCERT Solutions, Sample Papers, Notes, Videos

A ladder 5m long is leaning against a wall.the bottom of the ladder is pulled along the ground , away from the wall , at the rate of 3cm/s.how fast is its height on the wall decreasing when the foot of the ladder is 4m away from the wall
  • 1 answers

Anwesha Mishra 7 years, 11 months ago

Let y m be the height of the wall at which the ladder touches. Also, let the foot of the ladder be x maway from the wall.

Then, by Pythagoras theorem, we have:

x2 + y2 = 25 [Length of the ladder = 5 m]

⇒y=25−x2−−−−−−√
Then, the rate of change of height (y) with respect to time (t) is given by,

dydx=−x25−x2−−−−−−√.dxdt
It is given that

dxdt=2cm/s.
∴dydt=−2x25−x2−−−−−−√
Now, when x = 4 m, we have:

∴dydt=−2×425−42−−−−−−√=−83
Hence, the height of the ladder on the wall is decreasing at the rate of

83
https://examin8.com Test

Related Questions

Y=sin√ax^2+√bx+√c
  • 0 answers
Three friends Ravi Raju
  • 0 answers

myCBSEguide App

myCBSEguide

Trusted by 1 Crore+ Students

Test Generator

Test Generator

Create papers online. It's FREE.

CUET Mock Tests

CUET Mock Tests

75,000+ questions to practice only on myCBSEguide app

Download myCBSEguide App