ExamBro
ExamBro
KCET · Physics · Motion In Two Dimensions

Two bodies are projected with the same velocity. If one is projected at an angle of \(30^\circ\) and the other at \(45^\circ\) to the horizontal, then the ratio of maximum heights attained is

  1. A \(3:1\)
  2. B \(1:2\)
  3. C \(4:1\)
  4. D \(1:3\)
Verified Solution

Answer & Solution

Correct Answer

(B) \(1:2\)

Step-by-step Solution

Detailed explanation

The maximum height attained by a projectile is given by \(H = \dfrac{u^2 \sin^2 \theta}{2g}\).

For the first body, \(\theta_1 = 30^\circ\):
\(H_1 = \dfrac{u^2 \sin^2 30^\circ}{2g} = \dfrac{u^2}{2g} \left(\dfrac{1}{2}\right)^2 = \dfrac{u^2}{8g}\)

For the second body, \(\theta_2 = 45^\circ\):
\(H_2 = \dfrac{u^2 \sin^2 45^\circ}{2g} = \dfrac{u^2}{2g} \left(\dfrac{1}{\sqrt{2}}\right)^2 = \dfrac{u^2}{4g}\)

The ratio of maximum heights is:
\(\dfrac{H_1}{H_2} = \dfrac{\dfrac{u^2}{8g}}{\dfrac{u^2}{4g}} = \dfrac{4}{8} = \dfrac{1}{2}\)

Thus, the ratio is \(1:2\).

Answer: \(1:2\)