Solving Word Problems Using Quadratic Solutions

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

A diver is standing on a platform above the pool. He jumps form the platform with an initial upward velocity of 8 ft/s. Use the formula: h(t) = −16 t² + 8t + 24

How high is the platform? (Hint: find y-intercept.)

• .25 ft

• 24 ft

• 25 ft

• 8 ft

A kid launches a rock off of a cliff. The height of the rock after t seconds can be modeled by the graph shown. What is the height of the cliff?

• 1.094 ft

• 174.141 ft

• 155 ft

• 4.393 ft

• None of the above

A kid launches a rock off of a cliff. The height of the rock after t seconds can be modeled by the graph shown. When does the rock hit the ground?

• 1.094 seconds

• 174.141 seconds

• 155 seconds

• 4.393 seconds

• None of the above

The sum of a number and its square is 72. Find the number(s).

• 8 or 9

• 8 or -9

• -8 or 9

• -8 or -9

Tags

CCSS.8.EE.A.2

A kid launches a rock off of a cliff. The height of the rock after t seconds can be modeled by the graph shown. What is the maximum height the rock reaches ?

• 1.094 ft

• 174.141 ft

• 155 ft

• 4.393 ft

• None of the above

A kid launches a rock off of a cliff. The height of the rock after t seconds can be modeled by the graph shown. How long does it take the rock to reach its maximum height?

• 1.094 seconds

• 174.141 seconds

• 155 seconds

• 4.393 seconds

• None of the above

If a toy rocket is launched from the ground and its height h after t seconds is given by the function h(t) = -8t² +64t.

When will the object reach its maximum height?

• 128 ft

• 0 seconds

• 0 ft

• 4 seconds

Your nephew is standing on his deck and tosses his toy up into the air. The equation h= -2t^2+5t+3 models the toy’s height h in feet from the ground at t seconds after he threw it. How high is the toy after 2 seconds?

• 1.25

• 3

• 4

• 5
  

• 6.13
  

A dolphin jumps from the water. The function h(t) = -16t² + 80t models the dolphin's height at any given time, t. What is the maximum height the dolphin jumps? What are you solving for?

• solutions

• y-intercept

• axis of symmetry

• y-value of the vertex