Pls help me guys :( you guys are talented

the initial vertical velocity of a rocket shot straight up is 42 meters per second. How long does it take for the rocket to retu

Snowcat [4.5K]

It takes 4.3 seconds for the rocket to return to earth.

The equation is:
$0=-9.8t^2+v_0t+h_0$
where -9.8m/sec² is the acceleration due to gravity, v₀ is the initial velocity, and h₀ is the initial height. We will go from the assumption that the rocket is launched from the ground, so h₀=0, and we are told that the initial velocity, v₀, is 42. This gives us:

$0=-9.8t^2+42t$

We will use the quadratic formula to solve this. The quadratic formula is:
$x=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

Plugging in our information we have:
$t=\frac{-42\pm \sqrt{42^2-4(-9.8)(0)}}{2(-9.8)}
\\
\\=\frac{-42\pm \sqrt{1764-0}}{-19.6}
\\
\\=\frac{-42\pm \sqrt{1764}}{-19.6}
\\
\\=\frac{-42\pm 42}{-19.6}=\frac{-42-42}{-19.6} \text{ or } \frac{-42+42}{-19.6}
\\
\\=\frac{-84}{-19.6}\text{ or }\frac{0}{-19.6}
\\
\\=4.3\text{ or }0$

x=0 is when the rocket is launched; x=4.3 is when the rocket lands.

8 0

3 years ago

(System of inequality word problem.)

lana66690 [7]

Answer:

C

Step-by-step explanation:

Because nintendo price=300$

He has 215$

1 chore he does=7$

Meaning if he did 10 chores he get's 70$ added so he did 10 now he has 285$ If he does 2 more chores that is 14$ more added.

So he now has 299$ so he done 12 chores and he needs 1 more dollar so if he did 1 more he gets 306$ and that was the least amount of chores he could do if he wanted 300$

And there's your answer

Hope this helps have a awesome day:)

8 0

1 year ago

Which graph shows the solution to this system of inequalities? y>-1/3x+1 y>2x-3

Mademuasel [1]

Given:

The system of inequalities is:

$y>-\dfrac{1}{3}x+1$