In the annual battle of the dorms, students gather on the roofs of Jackson and W

Question

In the annual battle of the dorms, students gather on the roofs of Jackson and Walton dorms to launch water balloons at each other with slingshots. The horizontal distance between the buildings is 35.0 m, and the heights of the Jackson and Walton buildings are, respectively, 15.0 m and 23.0 m. The first balloon launched by the Jackson team hits Walton dorm 1.80 s after launch, striking it halfway between the ground and the roof. Ignore air resistance. (a) Find the direction of the balloon's initial velocity. Give your answer as an angle (in degrees) measured above the horizontal. (b) A second balloon launched at the same angle hits the edge of Walton's roof. Find the initial speed of this second balloon.

Explanation / Answer

(a)
The first balloon travels for 1.8 s.

Since we know both the horizontal distance and

the balloon's flight time, we know its horizontal velocity:

vx = dx / dt = 38 m / 1.8 s = 21.11 m/s horizontally

We also know it was launched from an initial height of 17.0 m and
impacted 11.0 m above the ground (half of Walton dorm's height).
That means its overall vertical displacement was -6.0 m.
we can work out the initial vertical velocity using the formula:

dy = vy*t + 1/2 at

Related Questions

Navigate

• Browse (All)
• Browse I
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.