Question

The highest barrier that a projectile can clear is $14m$, when the projectile is launched at an angle of $30.0$ degrees above the horizontal. What is the projectile's launch speed? (in m/s)

• A. $33.1$
  
• B. $33.3$
  
• C. $33$
  
• D. $36$
  

Answer 1

Answer: (A)

$33.1$

Maximum height reached $H=14m$
Projection angle $\theta ={30}^o$
Using $H=\frac{u^2{\sin }^2\theta }{2g}$
$\therefore 14=\frac{u^2{\sin }^{2}30}{2\times 9.8}=\frac{u^2\times (0.5{)}^2}{2\times 9.8}$
$⟹u=33.1m/s$