Answer:
The horizontal displacement of a projectile launched at an angle.
Step-by-step explanation:
If the formula used by Rosa is
where
is the initial speed of the object or the velocity with which the object is thrown. There are two component of velocities i.e. horizontal and vertical. If
is the angle with horizontal. We know that distance travelled is given by :

So, Rosa is finding the horizontal displacement of a projectile launched at an angle.