Ask Experts Questions for FREE Help !
Ask
    488036's Avatar
    488036 Posts: 2, Reputation: 1
    New Member
    		  
    #1

    Jan 4, 2008, 02:55 PM
    a quadratic
    f(t)= -5t^2 +20t
    when a football is kicked with a vertical speed of 20m/s its height after t seconds is that equation but I can't understand how long the football in the air, and after how long after it has been kicked is the football at a height of 15m?
    ISneezeFunny's Avatar
    ISneezeFunny Posts: 4,175, Reputation: 821
    Ultra Member
    		  
    #2

    Jan 4, 2008, 03:00 PM
    how long is the football in the air?

    well, the football is in the air as long as it's not on the ground. Since f(t) is the height measurement, solve the quadratic for

    0 = -5t^2 + 20t

    solve for t. you will get 2 answers... one when you first kick it off the ground, the other when it lands back down to the ground.

    for the second part, since f(t) is the height, substitute 15 for f(t)

    15 = -5t^2 + 20t

    solve for t. you will get two answers again. One answer when the ball hits 15 m while going up, and another one when the ball hits 15 m coming back down.
Not your question? Ask your question View similar questions
 

Question Tools Search this Question
Search this Question:

Advanced Search


Check out some similar questions!

Quadratic function [ 1 Answers ]

I have another question! I really am lost? I don't get those.. Chris cuts half a rectangular lawn, 40m by 30m by moving strips of equal width around perimeter. Jerri cuts the small rectangle left How wode a strip does Chris cut so that they share equally? Help!

Quadratic Functions [ 1 Answers ]

Hi, I am a first time user so hope I am doing this correctly. The original home was H(t)=-16t(squared)+1450. I came up with [-16(1)squared + 1450 + 16 (0)squared - 1450 / 1 = -16. I am pretty sure the answer is correct however can't figure out how to plug it into a TI-83 to graph it. Thanks,

Quadratic functions [ 2 Answers ]

Find the equation of the resulting parabola when y= -2x^2+4x+1 is translated -3 units along the x-axis and 2 units along the y-axis.

Quadratic formula [ 5 Answers ]

Hey I need some help with this question; A tank can be filled in 6 hrs using two pipes. The larger pipe alone would fill it 5 hrs sooner than the smaller pipe alone. How long would each pipe alone take?

Quadratic equations [ 1 Answers ]

A rectangular animal pen with the area 1200m has one sidealong a barn. The other three sides are enclosed by a 100m fencing. Find the dimensions of the pen.

View more questions Search