Applications of Quadratic Functions

A projectile is launched from a point above the ground. The height at ground level is given by the equation ℎ = −3𝑡 ² + 24𝑡, where h is the height in meters and t is the time in seconds. . What is the maximum height it can be reach?

• A. 40 m

• B. 35 m

• C. 24 m

• D. 48 m

A fountain shoots water in an arc over a lake that can be modeled by the graph of the equation y= -0.4x² + 8x where x is the horizontal distance (in feet) from the fountain base and y is the height (in feet) above the river.  How high does the water go?

• It goes 11.78 feet high

• It goes 20 feet high

• It goes 40 feet high

• It goes 10 feet high

A raft is dropped from a helicopter 256 feet in the air above the ocean.  Its approximate height, h, after t seconds is given by the function h(t) = -16t² + 256.  How many seconds did it take the raft to hit the water? 

• -4

• 2

• 4

• 8

What is the initial (starting) height of an object following this path?  h(t) = -16t² +20t + 6

• -16 feet 

• 0 feet

• 20 feet 

• 6 feet 

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.

Which one are we looking for?

Elliot wants to know how high the soccer ball will get if he kicks it straight up in the air.

• x at vertex

• y at vertex

• positive zero

• y-intercept

Which one are we looking for? Jaiden wanted to know the initial height of a baseball when it was hit at home plate.

• x at vertex

• y at vertex

• positive zero

• y-intercept

Suppose the path of an object that has been thrown is represented by (t-4)(t+2)=0. How long did it take for the object to hit the ground?

• 4 seconds

• -2 seconds

• -2 and 4 seconds

If I want to see the initial height of an object, I should _____________.

• Substitute x = 0 into the equation and evaluate.

• Use x = (-b /2a) as my answer.

• Find the y-coordinate of the vertex. 

• Set my equation = 0 and solve.

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