The function H(t) = -16t2 + vt + s shows the height H (t), in feet, of a projectile launched vertically from s feet above the ground after t seconds. The initial speed of the projectile is v feet per second.

Part A: The projectile was launched from a height of 90 feet with an initial velocity of 50 feet per second. Create an equation to find the time taken by the projectile to fall on the ground. (2 points)

Question

The function H(t) = -16t2 + vt + s shows the height H (t), in feet, of a projectile launched vertically from s feet above the ground after t seconds. The initial speed of the projectile is v feet per second.

Part A: The projectile was launched from a height of 90 feet with an initial velocity of 50 feet per second. Create an equation to find the time taken by the projectile to fall on the ground. (2 points)

anonymous · Answer

Part B: What is the maximum height that the projectile will reach? Show your work. (2 points)

Part C: Another object moves in the air along the path of g(t) = 28 + 48.8t where g(t) is th

anonymous · Answer

@paki Could you please help?

anonymous · Answer

@mathmate Could you please help?

mathmate · Answer

Yes, I am reading the question.

anonymous · Answer

im sorry. Ty @mathmate :)

mathmate · Answer

The relation of height as a function of time has already been supplied, right?

anonymous · Answer

Im not sure if i follow.

mathmate · Answer

Given:
The function H(t) = -16t2 + vt + s shows the height H (t), in feet, of a projectile launched vertically from s feet above the ground after t seconds. The initial speed of the projectile is v feet per second.

mathmate · Answer

H(t) is the height of projectile t seconds after lanching, and v is the initial velocity, and s is the initial height.  Do you have the same understanding?

anonymous · Answer

Yes.

mathmate · Answer

According to question part A, do you know v and s?

anonymous · Answer

Im just not sure how to set a equation up for this.

anonymous · Answer

It does not give that to us though I think.

mathmate · Answer

You don't need to set up anything.
You only have to use what is given for you.
According to question part A, do you know v and s?

anonymous · Answer

I do not.

mathmate · Answer

Rule number 1:
Whenever in doubt, read the question again!  :)

anonymous · Answer

*feels really dumb*

anonymous · Answer

so v is 50

mathmate · Answer

Not at all, you were just intimidated by the wording of the question.
Digest what they give you:
"The projectile was launched from a height of 90 feet with an initial velocity of 50 feet per second."

mathmate · Answer

|dw:1405452474172:dw|

mathmate · Answer

Yes, v=50.
What else?

anonymous · Answer

the height is 90 but..