ExamBro
ExamBro
TS EAMCET · Maths · Application of Derivatives

If a balloon lying at an altitude of 30 m from an observer at a particular instant is moving horizontally at the rate of \(1 \mathrm{~m} / \mathrm{s}\) away from him, then the rate at which the balloon is moving away directly from the observer at the \(40^{\text {th }}\) second is (in \(\mathrm{m} / \mathrm{s}\) )

  1. A \(1.2\)
  2. B \(0.9\)
  3. C \(0.6\)
  4. D \(0.8\)
Verified Solution

Answer & Solution

Correct Answer

(D) \(0.8\)

Step-by-step Solution

Detailed explanation

\( x = 1 \, \mathrm{m/s} \times 40 \, \mathrm{s} = 40 \, \mathrm{m} \) \( z = \sqrt{x^2 + h^2} = \sqrt{40^2 + 30^2} = \sqrt{1600 + 900} = \sqrt{2500} = 50 \, \mathrm{m} \) \( \frac{dz}{dt} = \frac{x}{z} \frac{dx}{dt} = \frac{40}{50} \times 1 = 0.8 \, \mathrm{m/s} \)