Question

A projectile is launched with an unknown initial speed at an angle of 55 degrees above the horizontal. The projectile lands at the same height from which it was launched 200 m from the launch site. What was the initial speed?

Answer 1

Given data

*The given horizontal range is R = 200 m

*The given angle is

$\theta=55^0$

The formula for the horizontal range is given as

$R=\frac{u^2\sin 2\theta}{g}$

Substitute the known values in the above expression as

$\begin{gathered} 200=\frac{u^2\sin (2\times55^0)}{(9.8)} \\ u=44.6\text{ m/s} \end{gathered}$

Hence, the initial speed of the projectile is u = 44.67 m/s