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3 years ago

6

DeSean throws a ball up with an initial vertical velocity of 30 ft/s from a platform that is at ground level. How long will the

ball be in the air?

2 answers:

max2010maxim [7]3 years ago

5 0

h=h+vi t-4.9t^2

h=h=0

0=vi t-4.9t^2= t(vi-4.9t)

t= 30/4.9 m/s

Vilka [71]3 years ago

5 0

Answer:

Time, t = 1.875 seconds

Step-by-step explanation:

It is given that,

Initial velocity of the ball, u = 30 ft/s

DeSean throws a ball from a platform that is at ground level. The equation of motion when an object is thrown vertically upward is given by the following equation as :

$h(t)=-16t^2+vt+h$

Here, h = 0 since, the ball is thrown up at the ground level. We have to determine the time when the ball be in air. The quadratic equation becomes :

$-16t^2+30t+0=0$

t = 1.875 seconds

So, the ball be in air for 1.875 seconds. Hence, this is the required solution.

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The length of a rectangle is 4 meters less than twice its width. The are of a rectangle is 70m^2. Find the dimensions of the rec

igomit [66]

Answer:

The length is 7 m

The width is 10 m

Step-by-step explanation:

length = x

width = 2x - 4

length * width = area

It is given that the area is 70 $m^{2}$

From there

x * (2x - 4) = 70

$2x^{2}$ - 4x = 70

$2x^{2}$ - 4x - 70 = 0

$x^{2}$ - 2x - 35 = 0

Now we have a quadratic equation, which is a $x^{2}$ + bx + c = 0, where a $\neq$ 0

In this equation a = 1, b = -2 and c = -35

Discriminant (D) formula is b² - 4ac

D = $-2^{2}$ - 4 * 1 * (-35) = 144 > 0

This discriminant is more than 0, so there are two possible x

Their formulas are $\frac{- b - \sqrt{D} }{2a}$ and $\frac{- b + \sqrt{D} }{2a}$

$x_{1}$ = $\frac{- (-2) - \sqrt{144} }{2}$ = -5 < 0 (the length of the rectangle has to be more than 0, so we don't use this x)

$x_{2}$ = $\frac{- (-2) + \sqrt{144} }{2}$ = 7 > 0 (this one is right)

Calculating the dimensions

length = x = 7 (m)

width = 2x - 4 = 2 * 7 - 4 = 10 (m)

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3 years ago

What is the slope of-x²+8x+20

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2 years ago

If f(x) = 7x+6 and g(x)=8x-4 find f(g(-2))

sp2606 [1]

Answer:

$f(g(-2))=-134$

Step-by-step explanation:

So we have the two functions:

$f(x)=7x+6\text{ and } g(x)=8x-4$

And we want to find f(g(-2)).

First, let's find g(-2):

$g(-2)=8(-2)-4$

Multiply:

$g(-2)=-16-4$

Subtract:

$g(-2)=-20$

Now, substitute:

$f(g(-2))=f(-20)$

Now, find the value of f(-20):

$f(-20)=7(-20)+6$

Multiply:

$f(-20)=-140+6$

Add:

$f(-20)=-134$

So:

$f(g(-2))=-134$

And we're done!

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3 years ago

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2 years ago

Please help me <br> i'll mark u as brainiest if u get it right

Black_prince [1.1K]

Answer: a) 46 minutes
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The basic knowledge for this is that 60 minutes = 1 hour

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10:34 will become 11:00 at 10:60 right? Clock's generally don't show 10:60 but goes directly to 11:00 after 1 minute is passed at 10:59. So from 10:34 to 11:00, it takes 26 minutes. Remember the bus reaches at 11:20 so from 11:00 to 11:20, it takes 20 minutes. Now add them up:
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Here you go! Total 46 minutes from Mosley to Bamford.

<u>b)</u> From question b, we can see that Trina did not ride the first bus or by any chance missed it because the bus left at 10:14 and she is at the station at 10:15. Now think it from your perspective! You missed the first bus and you are in a big rush. So to reach your destination as early as possible, you will obviously take the next earliest bus. The next bus is at 10:24 (Belton). So if we take the 10:24 bus in Belton, it reaches at 10:47 in Garton.

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2 years ago