ExamBro
ExamBro
KCET · Physics · Motion In Two Dimensions

The trajectory of a projectile projected from origin is given by the equation \( y=x-\frac{2 x^{2}}{5} \). The initial velocity of the projectile is

  1. A \( 25 \mathrm{~ms}^{-1} \)
  2. B \( \frac{2}{5} \mathrm{~ms}^{-1} \)
  3. C \( \frac{5}{2} \mathrm{~ms}^{-1} \)
  4. D \( 5 \mathrm{~ms}^{-1} \)
Verified Solution

Answer & Solution

Correct Answer

(D) \( 5 \mathrm{~ms}^{-1} \)

Step-by-step Solution

Detailed explanation

(D)
\(y=x-\frac{2 x^{2}}{5} \)
\( \tan \theta=1 \)
\( \theta=45^{\circ} \)
\( \frac{g}{2 u^{2} \cos ^{2} \theta}=\frac{2}{5} \)
\( \frac{10}{2 u^{2} \frac{1}{2}}=\frac{2}{5} \)
\( u^{2}=\frac{50}{2}=25 \)
\( u=5 m s^{-1}\)