Answer:
The initial speed of the golf ball was 25 m/s.
Explanation:
To find the initial speed of a projectile motion we must first find the motion equation corresponding to each axis:
For X axis we have an Uniform Rectilinear Motion, since no forces act along it:
, where stands for the initial speed component on x axis, and is the initial position on x axis (zero, in this case).
For Y axis we have a Constant Acceleration Motion, since the gravitational force acts along it:
, where <em>g </em>is the acceleration of gravity, stands for the initial speed component on y axis, and is the initial position on y axis (zero, in this case).
We can describe the initial speed's components as follow:
and
Keeping this in mind, we're just three steps away from the answer.
The first step is expressing <em>t </em>in terms of <em>x</em>:
The second step is replacing this expression for <em>t</em> on the y axis equation:
Finally, we use the fact that when x=55.2312 m the golf ball lands, it means y=0 m, and resolve the equation for
Obtaining