Quadratic Applications Vertex Form

When I want to find the maximum or minimum height of an object, I should_____

• Set the equation = 0 and solve.

• Use x = (-b/2a) as my answer.

• Substitute x = 0 into the equation.

• Find the y-coordinate for the vertex.

An object in launched directly upward at 64 feet per second (ft/s) from a platform 80 feet high. Its height is represented by the equation 
s(t) = –16t² + 64t + 80.
What will be the object's maximum height? 

• 2 ft

• 80 ft

• 144 ft

• 64 ft

The function f(t) = -5t²+20t + 60 models the approximate height of an object t seconds after it is launched. How many seconds does it take the object to hit the ground?

• 4 seconds

• -2 seconds

• 6 seconds

• 9 seconds

If a toy rocket is launched vertically upward from ground level with an initial velocity of 128 feet per second, then its height h after t seconds is given by the equation
h(t) = -16t² +128t  
When will the object reach its maximum height?

• 4 ft

• 0 seconds

• 0 ft

• 4 seconds

Identify the vertex and whether the graph opens up or down. (a)  

• (5, 2); opens up

• (5, 2); opens down

• (-5, 2); opens up

• (-5, 2); opens down

The graph of a quadratic function is shown. The vertex and two points are labeled. Drag and drop the numbers and operations to write the equation for the parabola in vertex form. y = ​ (a)   (x​​ (b)   (c)   )² - (d)  

• -

• 1

• 6

• 12

• 4

• 8

• +

The graph of a quadratic function is shown. The vertex and two points are labeled. Drag and drop the numbers and operations to write the equation for the parabola in vertex form. y = ​ (a)   (x​​ (b)   (c)   )² - (d)  

• -

• 1

• 6

• 12

• 4

• 8

• +

Which of the following is the correct equation for the given graph? (a)  

• f(x) = -(x + 2)^2 - 4

• f(x) = -(x - 2)^2 - 4

• f(x) = -3(x - 2)^2 - 4

• f(x) = -3(x + 2)^2 - 4

A ball is thrown into the air with an upward velocity of 100 ft/s. Its height, h, after t seconds is given by the function
 h = -16t² + 64t + 960.
How many seconds did it take for the ball to reach its maximum height?

• 10 seconds

• 64 seconds

• 960 seconds

• 2 seconds

If I want to find out when an object hits the ground, I should _________.

• Use x = (-b/2a) as my answer.

• Set my equation = 0 and solve.

• Replace x with 0 and evaluate.

• Find the y-coordinate of the vertex.