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3 years ago

I WILL GIVE BRAINLIEST ANSWER OUT. 20 POINTS!

1 answer:

5 0

1.56X10^4 means 1.56 moved decimal to right 4 places or 15600
4hr and 16mins
convert to seconds
4 times 60=240 min
240 mini times 60=14400
16min times 60=960

add
14400+960=15360

15360<15600

miguel ran faster

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A rock thrown vertically upward from the surface of the moon at a velocity of 36m/sec reaches a height of s = 36t - 0.8 t^2 met

Verdich [7]

Answer:

a. The rock's velocity is $v(t)=36-1.6t \:{(m/s)}$ and the acceleration is $a(t)=-1.6 \:{(m/s^2)}$

b. It takes 22.5 seconds to reach the highest point.

c. The rock goes up to 405 m.

d. It reach half its maximum height when time is 6.59 s or 38.41 s.

e. The rock is aloft for 45 seconds.

Step-by-step explanation:

Velocity is defined as the rate of change of position or the rate of displacement. $v(t)=\frac{ds}{dt}$
Acceleration is defined as the rate of change of velocity. $a(t)=\frac{dv}{dt}$

The rock's velocity is the derivative of the height function $s(t) = 36t - 0.8 t^2$

$v(t)=\frac{d}{dt}(36t - 0.8 t^2) \\\\\mathrm{Apply\:the\:Sum/Difference\:Rule}:\quad \left(f\pm g\right)'=f\:'\pm g'\\\\v(t)=\frac{d}{dt}\left(36t\right)-\frac{d}{dt}\left(0.8t^2\right)\\\\v(t)=36-1.6t$

The rock's acceleration is the derivative of the velocity function $v(t)=36-1.6t$

$a(t)=\frac{d}{dt}(36-1.6t)\\\\a(t)=-1.6$

b. The rock will reach its highest point when the velocity becomes zero.

$v(t)=36-1.6t=0\\36\cdot \:10-1.6t\cdot \:10=0\cdot \:10\\360-16t=0\\360-16t-360=0-360\\-16t=-360\\t=\frac{45}{2}=22.5$

It takes 22.5 seconds to reach the highest point.

c. The rock reach its highest point when t = 22.5 s

Thus

$s(22.5) = 36(22.5) - 0.8 (22.5)^2\\s(22.5) =405$

So the rock goes up to 405 m.

d. The maximum height is 405 m. So the half of its maximum height = $\frac{405}{2} =202.5 \:m$

To find the time it reach half its maximum height, we need to solve

$36t - 0.8 t^2=202.5\\36t\cdot \:10-0.8t^2\cdot \:10=202.5\cdot \:10\\360t-8t^2=2025\\360t-8t^2-2025=2025-2025\\-8t^2+360t-2025=0$

For a quadratic equation of the form $ax^2+bx+c=0$ the solutions are

$x_{1,\:2}=\frac{-b\pm \sqrt{b^2-4ac}}{2a}$

$\mathrm{For\:}\quad a=-8,\:b=360,\:c=-2025:\\\\t=\frac{-360+\sqrt{360^2-4\left(-8\right)\left(-2025\right)}}{2\left(-8\right)}=\frac{45\left(2-\sqrt{2}\right)}{4}\approx 6.59\\\\t=\frac{-360-\sqrt{360^2-4\left(-8\right)\left(-2025\right)}}{2\left(-8\right)}=\frac{45\left(2+\sqrt{2}\right)}{4}\approx 38.41$

It reach half its maximum height when time is 6.59 s or 38.41 s.

e. It is aloft until s(t) = 0 again

$36t - 0.8 t^2=0\\\\\mathrm{Factor\:}36t-0.8t^2\rightarrow -t\left(0.8t-36\right)\\\\\mathrm{The\:solutions\:to\:the\:quadratic\:equation\:are:}\\\\t=0,\:t=45$

The rock is aloft for 45 seconds.

5 0

3 years ago

Total area of two room <br> Help due soon (no link)

AlladinOne [14]

The answer is B, 2136

Explanation:
48-28 = 20. Now 20 times 20 equals 400, now remember that number.
Now 28 times 62 equals 1,736.
Now back to 400.
400+1736 equals 2,136.

Hope I helped you, please tell me if I am correct or not.

Enjoy your day!
:)

4 0

2 years ago

!!!please for the love of God help me!!!

Grace [21]

<h3>Given :-</h3>

$\\$

x=y-1
x+2y=8

$\\$

$\\$

Value of x
Value of y

$\\$

<h3>Solution:-</h3>

Let say it is first equation:-

x=y-1. . . . (1)

and this is second equation:-

x+2y=8 . . . . (2)

$\\ \\$

Simplifying 1 equation:-

x = y - 1
x +1 = y
y = x + 1

Put this value of y in second equation.

$\\$

$\dashrightarrow \sf \: x+2y=8$

$\\$

$\dashrightarrow \sf \: x+2(x + 1)=8$

$\\$

$\dashrightarrow \sf \: x+2x +2=8$

$\\ \\$

$\dashrightarrow \sf \: 3x +2=8$

$\\ \\$

$\dashrightarrow \sf \: 3x=8 - 2$

$\\ \\$

$\dashrightarrow \sf \: 3x=6$

$\\ \\$

$\dashrightarrow \sf \: x=6 \div 3$

$\\ \\$

$\dashrightarrow \sf \: x= \bf2$

$\\$

to find value of y :-

y = x + 1

y = 2 + 1

y = 3

$\\$

verification:-

$\\$

1 equation:-

x = y - 1

put value of x and y

2 = 3 - 1

2 = 2

LHS = RHS

Hence verified!

$\\$

2 equation:-

$\\$

x+2y=8

put value of x and y

2 + 2 × 3 = 8
2 + 6 = 8
8 = 8

LHS = RHS

Hence verified!

$\\$

Both equation verified!

.°. value of x and y is 2 and 3 respectively

7 0

2 years ago

Kenny is 8 years older than Andrew. Tim is 3 times

9966 [12]

Answer:

Kenny is 18 years old Andrew is 10 years old Tim is 30 years old and Cameron is 5 years old

Step-by-step explanation:

Let a be Kenny's age , b be Andrew's age , c be Tim's age , d be Cameron's age

( b < a , b<c , d<b)

Kenny is 8 years older than Andrewn = > a = b + 8 (1)

Tim is 3 times as old as Andrew => c = 3 . b (2)

Cameron is 5 years younger than Andrew => d = b-5 (3)

The combined age of the four is 63 => a+b+c+d = 63 (4)

(1),(2),(3),(4) => b+8 + b + 3b + b-5 = 63 <=> 6b + 3 = 63 <=> b = 10

=> a= 10+8 =18, c = 3 . 10 = 30, d= 5

5 0

3 years ago

This exercise provides information about data in a survey of students. The survey included 58 students who smoke and 311 who don

Leviafan [203]

Answer:

0.157 is the proportion of students who smoke.

Step-by-step explanation:

We are given the following in the question:

Number of students who smoke = 58

Number of students who don't smoke = 311

Total number of students surveyed =

Number of students who smoke + Number of students who don't smoke

$= 58 + 311\\=369$

Proportion of students who smoke =

$=\displaystyle\frac{\text{Number of students who smoke}}{\text{Total number of students}}\\\\= \frac{58}{369}\\\\= 0.157$

Thus, 0.157 is the proportion of students who smoke.

5 0

3 years ago