Question

Single Correct Answer Type
At what angle with the horizontal should a ball be thrown so that its range $R$ is related to the time of flight as $R=5T^2$. Take $g=10m{s}^{-2}$:

• A. $30$
• B. $45$
• C. $60$
• D. $90$

Answer 1

The correct option is B $45$

$R=5T^2$

$\frac{v^{2}sin2\theta }{g}=5(\frac{2vsin\theta }{g}{)}^2$

$⟹sin2\theta =\frac{20si{n}^2\theta }{10}=2si{n}^2\theta$

$2sin\theta cos\theta =2si{n}^2\theta$

$⟹cos\theta =sin\theta$

$\therefore \theta ={45}^o$