(projectile motion critical values)
How high up off the ground did the golf ball sit before Evan swung his club and hit it?
Initial Height / y-intercept
The quadratic formula song we heard in class is sung to the tune of this popular children's song.
Pop Goes the Weasel
f(x)=ax^2+bx+c
In standard form above, when
a
is negative, the parabola faces
downward
What was the initial height?
5 feet
All Hallow's Eve / Samhain
How long was the golf ball in the air?
Zero / Root / x-intercept
The "hit the ground" point
The quadratic formula is made to calculate, at most, this many answers.
Two
f(x)=ax^2+bx+c
In standard form above, the y-intercept is this ordered pair.
(0,c)
At what time does the projectile hit its peak height?
1.688 seconds
The first name of Dr. Frankenstein
Victor
When did the golf ball hit the peak of its path of flight?
x-value of vertex / maximum height
What does this mean?
\pm
plus or minus
The x-value of the vertex of
y=ax^2+bx+c
x=(-b)/(2a)
What is the maximum height of the projectile?
50.563 feet
"Trick or treat, _____________
give me something good to eat.
smell my feet
What was the distance to the ground when the golf ball was at its peak?
y-value of vertex / maximum height
The quadratic formula is used to calculate what?
x
or, the value of the input (x-axis) variable when the output (y-axis) variable is zero
or, the roots of the quadratic
How do you find the time at which a projectile hits the ground, given the equation
y=ax^2+bx+c?
x=(-b+-sqrt(b^2-4ac))/(2a)
For how many seconds is the projectile in the air?
3.465 seconds
Value, h(t) when t=2
The quadratic formula cannot be calculated (in traditional ways) when this is negative.
The value under the square root (called the discriminant)
If you have the x-value, how do you find the y-value of the vertex of
y=ax^2+bx+c
Plug it in for x in y=ax^2+bx+c
What number do we ignore here and why?
-0.09 because it's negative and doesn't apply to the situation
(there is no negative time)
Of all of the "halloween songs," this is considered the most popular of all time
"Thriller" by Michael Jackson