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kiruha [24]
3 years ago
14

The CHS baseball team wasn’t on the field and the batter popped the ball up.The equation b(t)= 80t-16t^2+3.5 represents the heig

ht of the ball above the ground in feet as a function of time in seconds. How long will the catcher have to get in position to catch the ball before it hits the ground? Round to the nearest second
Mathematics
2 answers:
Afina-wow [57]3 years ago
8 0

The given function is

b(t) = 80t-16t^2+3.5

Rearranging it we get

b(t) = -16t^2+80t+3.5

Now when the ball hits the ground

Height b(t) becomes 0.

So we have

-16t^2+80t+3.5=0

Comparing with

ax^2+bx+c

We get

a=-16, b=80 & c = 3.5

Substituting in the quadratic formula we get

t=\frac{-b+\sqrt{b^2-4ac}}{2a}  or  t=\frac{-b-\sqrt{b^2-4ac}}{2a}t=\frac{-80+\sqrt{80^2-4(-16)(3.5)}}{2(-16)}  =-0.04

OR

t=\frac{-80-\sqrt{80^2-4(-16)(3.5)}}{2(-16)} =5.04

But the time cannot be negative

So t = 5.04 seconds

Rounding to the nearest second we get

t = 5 seconds

jok3333 [9.3K]3 years ago
4 0
The answer to this question is 5 seconds.
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John runs to the market and comes back in 15 minutes. His speed on the way to the market is 5m/s and his speed on the way back i
katen-ka-za [31]

Answer:

The distance to the market is 2000 m

Step-by-step explanation:

∵ John runs to the market and comes back in 15 minutes

→ Change the min. to the sec. because the unit of his speed is m/s

∵ 1 minute = 60 seconds

∴ 15 minutes = 15 × 60 = 900 seconds

→ Assume that t1 is his time to the market and t2 is his time from

  the market

∵  t1 + t2 = 15 minutes

∴ t1 + t2 = 900 ⇒ (1)

→ Assume that the distance to the market is d

∵ His speed on the way to the market is 5m/s

∵ Time = Distance ÷ Speed

∴ t1 = d ÷ 5 ⇒ (1 ÷ 5 = 0.2)

∴ t1 = 0.2d ⇒ (2)

∵ His speed on the way back is 4m/s

∴ t2 = d ÷ 4 ⇒ (1 ÷ 4 = 0.25)

∴ t2 = 0.25d ⇒ (3)

→ Substitute (2) and (3) in (1)

∵ 0.2d + 0.25d = 900

∴ 0.45d = 900

→ Divide both sides by 0.45

∴ d = 2000 m

∴ The distance to the market = 2000 m

8 0
3 years ago
Find x for me i need help.
vesna_86 [32]

Answer:

X is 70 degrees

Step-by-step explanation:

In a triangle, all the angles add up to 180.

We can set up an equation:

48+62+x=180

x=180-(48+62)

x=70

5 0
3 years ago
Which shape has no parallel sides?<br> rectangle<br> trapezoid<br> square<br> triangle
nadezda [96]

Answer:

Triangle

Step-by-step explanation:

all of them have parallel sides except triangle

5 0
2 years ago
Read 2 more answers
In a study on the time that
krok68 [10]

The 95% confidence interval of the population mean, in years, is (4.3, 5.3). 4 years is not part of the confidence interval, which means that it contradicts the fact that 39% of students get their college degree in four years.

-----------------------------

To solve this question, we need to find the confidence interval for the amount of time it takes the students to get the degree.

We have the standard deviation for the sample, which means that the t-distribution is used to solve this question.

-----------------------------

The first step to solve this problem is finding how many degrees of freedom,which is the sample size subtracted by 1. So

df = 80 - 1 = 79

-----------------------------

95% confidence interval

Standard level of confidence, we have to find a value of T, which is found looking at the t table, with 79 degrees of freedom(y-axis) and a confidence level of 1 - \frac{1 - 0.95}{2} = 0.975. So we have T = 1.9905.

-----------------------------

The margin of error is:

M = T\frac{s}{\sqrt{n}} = 1.9905\frac{2.2}{\sqrt{80}} = 0.5

In which s is the standard deviation of the sample and n is the size of the sample.

-----------------------------

The lower end of the interval is the sample mean subtracted by M. So it is 4.8 - 0.3 = 4.3 years.

The upper end of the interval is the sample mean added to M. So it is 4.8 + 0.3 = 5.3 years.

-----------------------------

The 95% confidence interval of the population mean, in years, is (4.3, 5.3). 4 years is not part of the confidence interval, which means that it contradicts the fact that 39% of students get their college degree in four years.

A similar question is given at brainly.com/question/24278748

6 0
2 years ago
What is the value of x?<br><br><br><br> Enter your answer in the box.
elixir [45]
X = 28, hope this helps
5 0
3 years ago
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