Question

An egg is dropped from the window of am building. The height, in feet, of the egg (t)

seconds after it is thrown is represented by d=16^t-7t+61 . How many seconds after the egg is thrown will it be 10 feet from the ground?

Answer 1

Answer:

Therefore,

After 1.58 seconds  the thrown egg will it be 10 feet from the ground.

Step-by-step explanation:

Given:

An egg is dropped from the window of am building. The height, in feet, of the egg "t"  seconds after it is thrown is represented by

$d=-16t^{2}-7t+61$

To Find:

Time t = ? when d = 10

Solution:

$d=-16t^{2}-7t+61$ ...Given

Put d = 10  for time, t

$10=-16t^{2}-7t+61$

$16t^{2}+7t-51=0$

Which is a Quadratic Equation

We will calculate "t" by Formula Method

For a Quadratic Equation ax² + bx + c = 0 we have

$x=\dfrac{-b\pm\sqrt{b^{2}-4ac}}{2a}$

On Comparing we get

a = 16 , b = 7, c = -51

$t=\dfrac{-7\pm\sqrt{7^{2}-4\times 16\times -51}}{2\times 16}$

$t=\dfrac{-7\pm\sqrt{3313}}{32}$

$t = 1.58\ or\ t=-2.02$

As time cannot be negative

So, t = 1.58 s

Therefore,

After 1.58 seconds  the thrown egg will it be 10 feet from the ground.