Ask question

Ask question

All categories

3 years ago

8

A soccer player uses her head to hit a ball up in the air from a height of 2 meters with an initial vertical velocity of 5 meter

s per second. The height h in meters of the ball is given by \large h=-4.9t^2+5t+2 , where t is the time elapsed in seconds. How long will it take the ball to hit the ground if no other players touch it?

1 answer:

Mandarinka [93]3 years ago

3 0

Answer:1.32 s

Step-by-step explanation:

Given

The initial height of ball H=2 m

Initial velocity u=5 m/s

Height of ball at any instant is given by

$H=-4.9t^2+5t+2$

The ball will hit the ground when h=0

$-4.9t^2+5t+2=0\\4.9t^2-5t-2=0\\t=\dfrac{5\pm\sqrt{25+4(4.9)(2)}}{2\times 4.9}\\t=\dfrac{5\pm\sqrt{64.2}}{9.8}\\t=\dfrac{5+8.01}{9.8}=1.32\ s\quad\text{Neglecting negative value of t}$

You might be interested in

Suppose a student's score on a standardize test to be a continuous random variable whose distribution follows the Normal curve.

blsea [12.9K]

Answer:

a) Percentage of students scored below 300 is 1.79%.

b) Score puts someone in the 90th percentile is 638.

Step-by-step explanation:

Given : Suppose a student's score on a standardize test to be a continuous random variable whose distribution follows the Normal curve.

(a) If the average test score is 510 with a standard deviation of 100 points.

To find : What percentage of students scored below 300 ?

Solution :

Mean $\mu=510$ ,

Standard deviation $\sigma=100$

Sample mean $x=300$

Percentage of students scored below 300 is given by,

$P(Z\leq \frac{x-\mu}{\sigma})\times 100$

$=P(Z\leq \frac{300-510}{100})\times 100$

$=P(Z\leq \frac{-210}{100})\times 100$

$=P(Z\leq-2.1)\times 100$

$=0.0179\times 100$

$=1.79\%$

Percentage of students scored below 300 is 1.79%.

(b) What score puts someone in the 90th percentile?

90th percentile is such that,

$P(x\leq t)=0.90$

Now, $P(\frac{x-\mu}{\sigma} < \frac{t-\mu}{\sigma})=0.90$

$P(Z< \frac{t-\mu}{\sigma})=0.90$

$\frac{t-\mu}{\sigma}=1.28$

$\frac{t-510}{100}=1.28$

$t-510=128$

$t=128+510$

$t=638$

Score puts someone in the 90th percentile is 638.

5 0

3 years ago

Every irrational number is a real justify your answer<br>

vivado [14]

Step-by-step explanation:

A real number MUST be able to be represented on a number line.

All numbers can be placed on a number line including irrational numbers.

Numbers like π can be placed between 3.13 and 3.15. It is a number.

Numbers like x or ∑ isn't a "REAL" number because it has no value.

5 0

3 years ago

Camille shaded 12/25 of a model. Write the decimal that represents the shaded portion of the model.

deff fn [24]

Answer: 12/25 is 0.48

because 12 divided into 25 equals 0.48

Step-by-step explanation:I’m sorry if I answered it too late

7 0

3 years ago

Which transformation can verify congruence by turning one triangle 90 degrees

Nezavi [6.7K]

The answer to the question of yours is A. Rotation Its not B. because the question is asking by turning one triangle 90 degrees. This would mean that B. is incorrect since its turning. It wouldn't be C. because it isn't translating 90 degrees left or right its turning. And it most definitely wouldn't be D. Dilation because the triangle isn't decreasing or enlarging. Hope this helped feel free to ask any more questions.

6 0

3 years ago

Read 2 more answers

What is the coordinate of the midpoint of segment AC

Aloiza [94]

Answer:

-5.5

Step-by-step explanation:

$\frac{-7+-4}{2}\\\\\frac{-11}{2}\\\\-5.5$

7 0

3 years ago