Part 1:
For this case we must see in the graph the axis of symmetry of the given parabola.
We have then that the axis of symmetry is the vertical line t = 2.
Answer:
The height of the javelin above the ground is symmetric about the line t = 2 seconds:
Part 2:
For this case, we must see the time t for which the javelin reaches a height of 20 feet for the first time.
We then have that when evaluating t = 1, the function is h (1) = 20. To do this, just look at the graph.
Then, we must observe the moment when it returns to be 20 feet above the ground.
For this, observing the graph we see that:
h (3) = 20 feet
Therefore, a height of 20 feet is again reached in 3 seconds.
Answer:
The javelin is 20 feet above the ground for the first time at t = 1 second and again at t = 3 seconds
These are the steps, with their explanations and conclusions:
1) Draw two triangles: ΔRSP and ΔQSP.
2) Since PS is perpendicular to the segment RQ, ∠ RSP and ∠ QSP are equal to 90° (congruent).
3) Since S is the midpoint of the segment RQ, the two segments RS and SQ are congruent.
4) The segment SP is common to both ΔRSP and Δ QSP.
5) You have shown that the two triangles have two pair of equal sides and their angles included also equal, which is the postulate SAS: triangles are congruent if any pair of corresponding sides and their included angles are equal in both triangles.
Then, now you conclude that, since the two triangles are congruent, every pair of corresponding sides are congruent, and so the segments RP and PQ are congruent, which means that the distance from P to R is the same distance from P to Q, i.e. P is equidistant from points R and Q
<span> By definition, the volume of a cone is given by:
</span>

<span> Where,
r: radius of the circular base of the cone.
h: cone height
The cone radius is given by:
</span>

<span> Where,
d: diameter of the circular base.
Substituting values we have:
</span>

<span>
Then, the volume will be:
</span>

<span>
Answer:
The volume of the cone is given by:
</span>

<span>
</span>