The mass, m grams, of a radioactive substance, present at time t days after first being observed, is given by the formula m=24e^-0.02t. Find
(i) the value of m when t=30.
(ii) the value of t when the mass is half of its value at t=0.
(iii) the rate at which the mass is decreasing when t=50.

Answers

Answer 1

Answer:

(i) The value of m when t = 30 is 13.2

(ii) The value of t when the mass is half of its value at t=0 is 34.7

(iii) The rate of the mass when t=50 is -0.18            

Step-by-step explanation:

(i) The m value when t = 30 is:

[tex] m = 24e^{-0.02t} = 24e^{-0.02*30} = 13.2 [/tex]

Then, the value of m when t = 30 is 13.2

(ii) The value of the mass when t=0 is:

[tex] m_{0} = 24e^{-0.02t} = 24e^{-0.02*0} = 24 [/tex]    

Now, the value of t is:

[tex] ln(\frac{m_{0}/2}{24}) = -0.02t [/tex]

[tex] t = -\frac{ln(\frac{24}{2*24})}{0.02} = 34.7 [/tex]

Hence, the value of t when the mass is half of its value at t=0 is 34.7

(iii) Finally, the rate at which the mass is decreasing when t=50 is:

[tex] \frac{dm}{dt} = \frac{d}{dt}(24e^{-0.02t}) = 24(e^{-0.02t})*(-0.02) = -0.48*                            (e^{-0.02*50}) = -0.18 [/tex]

Therefore, the rate of the mass when t=50 is -0.18.

I hope it helps you!                  


Related Questions

How many ways are there to put 9 differently colored beads on a $3\times3$ grid if the purple bead and the green bead cannot be adjacent (either horizontally, vertically, or diagonally), and rotations and reflections of the grid are considered the same

Answers

Answer:

20,160

Step-by-step explanation:

The arrangement of the 9 differently colored bead can be presented as follows;

[tex]\left[\begin{array}{ccc}1&2&3\\4&5&6\\7&8&9\end{array}\right][/tex]

Where 1 is the purple bead and 2 is the green bead, the number of ways of arrangement where the green bead cannot be adjacent to the green either horizontally, vertically, or diagonally

Placing the purple bead at 1, the location of the green bead = 3, 6, 7, 8, or 9

The number of ways = 5 ways × 7! ways of arranging the other beads

With the purple bead at 2, the location of the green bead = 7, 8, or 9

The number of ways = 3 × 7!

With the purple at 3, we also have 5 × 7! ways

At 4, similar to 2, we have, 3 × 7! ways

At 5, we have, 0 × 7!

At 6, we have 3 × 7!

For 7, 8, and 9, we have, (5 + 3 + 5) × 7!

The total number of ways = (5 + 3 + 5 + 3 + 0 + 3 + 5 + 3 + 5) × 7! ways

However, placing the purple bead at 1, 2, 3, 4, 6, 7, 8, and 9, (8 positions) can be taken as reflection and rotation of each other and can be considered the same

Therefore, the total number of acceptable ways = (5 + 3 + 5 + 3 + 0 + 3 + 5 + 3 + 5) × 7!/8 = 20,160 ways

FOR EASY BRAINLIEST ANSWER QUESTION BELOW!

1. Solve each word problem .twice a number added three times the sum of the number and 2 is more than 17. Find the numbers that satisfy condition

Answers

Answer:

28

Step-by-step explanation:

Using appropriate properties find 2/3 x (– 3/5) + 1/5 x 4/3 + 2/3 x ( – 3/2)=

Answers

Answer:

- [tex]\frac{17}{15}[/tex]      -1 [tex]\frac{2}{15}[/tex] , 1.13

Step-by-step explanation:

i need help in this question that is in the photo

Answers

The answer is A, 1. In the statement x^2 >x, if we try 4, 5 and 8 for x, we get 16, 25 and 64 for x^2. The statement is true. But if we try x = 1, when we square it we still have 1. Therefore for x=1, x^2>x is false.

1 + 3 + 4 = 4 + 3 + 1. What property is being described here?

Associative Property of Addition

Commutative Property of Addition

Associative Property of Multiplication

Answers

Answer: Commutative property of addition

Step-by-step explanation:

[tex]\huge\textsf{Hey there!}[/tex]

[tex]\large\text{1 + 3 + 4 = 4 + 3 + 1}[/tex]

[tex]\large\text{1 + 3 + 4}[/tex]

[tex]\large\text{4 + 4}[/tex]

[tex]\large\text{= \bf 8}[/tex]

[tex]\large\text{4 + 3 + 1}[/tex]

[tex]\large\text{7 + 1}[/tex]

[tex]\large\text{= \bf 8}[/tex]

[tex]\large\text{\bf 8 = 8}[/tex]

[tex]\large\textsf{We could remove Option C. because there’s no sign of multiplication.}[/tex]

[tex]\large\textsf{This leaves us to Option A and Option B because the equation(s) has}\\\large\textsf{sum/addition}[/tex]

[tex]\large\textsf{Associative Property of Addition formula is:}[/tex]

[tex]\bullet\large\text{ \bf (a + b) + c = a + (b + c)}[/tex]

[tex]\large\textsf{Commutative Property of Addition formula is:}[/tex]

[tex]\bullet\large\text{ \ \bf a + b = b + a}[/tex]

[tex]\boxed{\boxed{\large\textsf{Answer: \huge \bf Commutative Property of Addition}}}\\\boxed{\huge\textsf{(Option B.)}}\huge\checkmark[/tex]

[tex]\large\textsf{Good luck on your assignment and enjoy your day!}[/tex]

~[tex]\frak{Amphitrite1040:)}[/tex]

A particle is projected with a velocity of [tex]40ms^-^1[/tex] at an elevation of 60°. Calculate the vertical component of its velocity at a height of 50m. (Take g = [tex]9.8ms^-^2[/tex])
A. [tex]25\sqrt{3} ms^-^1\\\\B.20\sqrt{3} ms^-^1\\\\c. 2\sqrt{545} ms^-^1[/tex]

Answers

Answer:

[tex]2\sqrt{55}\text{ m/s or }\approx 14.8\text{m/s}[/tex]

Step-by-step explanation:

The vertical component of the initial launch can be found using basic trigonometry. In any right triangle, the sine of an angle is equal to its opposite side divided by the hypotenuse. Let the vertical component at launch be [tex]y[/tex]. The magnitude of [tex]40\text{ m/s}[/tex] will be the hypotenuse, and the relevant angle is the angle to the horizontal at launch. Since we're given that the angle of elevation is [tex]60^{\circ}[/tex], we have:

[tex]\sin 60^{\circ}=\frac{y}{40},\\y=40\sin 60^{\circ},\\y=20\sqrt{3}[/tex](Recall that [tex]\sin 60^{\circ}=\frac{\sqrt{3}}{2}[/tex])

Now that we've found the vertical component of the velocity and launch, we can use kinematics equation [tex]v_f^2=v_i^2+2a\Delta y[/tex] to solve this problem, where [tex]v_f/v_i[/tex] is final and initial velocity, respectively, [tex]a[/tex] is acceleration, and [tex]\Delta y[/tex] is distance travelled. The only acceleration is acceleration due to gravity, which is approximately [tex]9.8\:\mathrm{m/s^2}[/tex]. However, since the projectile is moving up and gravity is pulling down, acceleration should be negative, represent the direction of the acceleration.

What we know:

[tex]v_i=20\sqrt{3}\text{ m/s}[/tex] [tex]a=-9.8\:\mathrm{m/s^2}[/tex] [tex]\Delta y =50\text{ m}[/tex]

Solving for [tex]v_f[/tex]:

[tex]v_f^2=(20\sqrt{3})^2+2(-9.8)(50),\\v_f^2=1200-980,\\v_f^2=220,\\v_f=\sqrt{220}=\boxed{2\sqrt{55}\text{ m/s}}[/tex]

Round the $40435.29 to the nearest thousand dollar

Answers

Answer:

$40000

Step-by-step explanation:

The nearest thousand dollar is rounding the thousand value from its hundred value, which in this case is 4. Since 4 is less than half of 10, the thousand value must round down to $40000.

Answer:

$40000.00

Step-by-step explanation:

Report this answer if its incorrect ^_^

HELPP!
The functions f(x) and g(x) are described using the following equation and table:
f(x)=-4(1.09)x

Answers

Given:

The function is:

[tex]f(x)=-4(1.09)^x[/tex]

The table of values for the function g(x).

To find:

The equation that best compares the y-intercepts of f(x) and g(x).

Solution:

We have,

[tex]f(x)=-4(1.09)^x[/tex]

Putting [tex]x=0[/tex], we get

[tex]f(x)=-4(1.09)^0[/tex]

[tex]f(x)=-4(1)[/tex]

[tex]f(x)=-4[/tex]

So, the y-intercept of the function f(x) is -4.

From the given table of values, it is clear that the function f(x) passes through the point (0,-4). So, the y-intercept of the function g(x) is -4.

The y-intercept of f(x) is equal to the y-intercept of g(x).

Therefore, the correct option is A.

Answer:

A) The y-intercept of f(x) is equal to the y-intercept of g(x).

Use the distributive property to write the next step in simplifying the numerical expression. Use the asterisk symbol (*) to represent multiplication. Do not multiply factors fully and do not use spaces. 4(x + 9)​

Answers

Answer:

This is the expression:

4*x+4*9

People pack seeds into foils and store them in a seed vault. Each foil contains 500 seeds. If the vault has 145,000 seeds altogether, how many foils are in the vault?

Answers

Step-by-step explanation:

dbdhdhbdbshsjakkakkajnwbsbdbdbdbbdbdbdvdvdvvvddvvdvd

Answer:

290 foils

Step-by-step explanation:

145,000÷500=290

Find the perimeter of ΔJKL. Round your answer to the nearest tenth if necessary

Answers

The answer is x = 86.4, hope this helps

Answer:

3.25

Step-by-step explanation:

the triangle=15+9 8.5=3.25 in answer find x.8 ∆JKL OPTIMIZE 1 UP 3...

At a football stadium, 25% of the fans in the attendance were teenagers. If there were 190 teenagers at the football stadium, what was the total numbers of the people at the stadium?

Answers

Answer:

760

Step-by-step explanation:

25%= 190

100 = 25 × 4

100% (total number of people) = 190 × 4 = 760

I need some help with this one. Please give it a go! Thank you for your time.

Answers

Answer:

Step-by-step explanation:

Hello there

I'm also a student so I'm not 100% sure on this one, but I think I know.

Usually when you have functions you just replace the letters for their value:

f = 11x

g = x² - 6x + 3

h = -x + 4

Th exercise is asking for (g * h) (x)

Since there are parenthesis, here's what we have:

[(x² - 6x + 3)(-x + 4)](x)

Use the left side of the equation:

[(x² - 6x + 3)(-x + 4)](x)

And solve it:

-x³ + 6x² -3x + 4x² - 24x + 12

That's equal to

-x³ + 10x² -27x + 12

Multiply all that by that x on the left:

-x^4 + 10x³ -27x² + 12x

No idea if that's right so please tell me

Easy
a) -2,-5.-8.-11,...

Answers

Step-by-step explanation:

???????? what is easy??

What's your question

simplyfy using appropiate properties 1/4×2/5+-1/6×3/2+3/7×2/5 ​

Answers

Answer:

-1/35

Step-by-step explanation:

* means multiply

because of pemdas you should do three multiplication parts first

(1/4×2/5)+(-1/6×3/2)+(3/7×2/5)

1/20 - 3/12 + 6/35

3/60 - 15/60 + 6/35

-12/60 + 6/35

-1/5 + 6/35

-7/35 + 6/35

-1/35

Answer:

3/140

Step-by-step explanation:

1/4 × 2/5 + (-1/6) × 3/2 + 3/7 × 2/5 ​=

= 2/20 - 3/12 + 6/35

**********************************************

We need the LCD of 20, 12, 35.

20 = 2^2 * 5

12 = 2^2 * 3

35 = 5 * 7

LCD = 2^2 * 3 * 5 * 7 = 420

**********************************************

= 42/420 - 105/420 + 72/420

= 9/420

= 3/140

look at image for question and answers​

Answers

Answer:

ANSWER :

it's x + 3 + x

What is the equation of the following line?
(-4, 8)
(0,0)

Answers

Answer

Step-by-step explanation:

y = -2x + 0

Therefore; y = -2x

jayce travels 30 miles per hour in her car.how many miles does she travel in 4 hours

Answers

Answer:

120 miles

Step-by-step explanation:

30 miles per hour * 4 hours

120 miles

Answer:

She travels 120 miles in 4 hours.

Step-by-step explanation:

She travel in 4 hours = 30 miles × 4 = 120 miles

She travels 120 miles in 4 hours

Which of the following inequalities matches the graph?

Answers

Answer:

second one

Step-by-step explanation:

just read where the purple line finishes on the x axis, in this case it’s 5 so it’s greater than 5 or equal to it.

does the point (-4, 2) lie inside or outside or on the circle x^2 + y^2 = 25?​

Answers

Given equation of the Circle is ,

[tex]\sf\implies x^2 + y^2 = 25 [/tex]

And we need to tell that whether the point (-4,2) lies inside or outside the circle. On converting the equation into Standard form and determinimg the centre of the circle as ,

[tex]\sf\implies (x-0)^2 +( y-0)^2 = 5 ^2[/tex]

Here we can say that ,

• Radius = 5 units

• Centre = (0,0)

Finding distance between the two points :-

[tex]\sf\implies Distance = \sqrt{ (0+4)^2+(2-0)^2} \\\\\sf\implies Distance = \sqrt{ 16 + 4 } \\\\\sf\implies Distance =\sqrt{20}\\\\\sf\implies\red{ Distance = 4.47 }[/tex]

Here we can see that the distance of point from centre is less than the radius.

Hence the point lies within the circle .

Have a good day everybody.......

Answers

thank you, you too! :D

Thank you and you too

Which of the following statements are always true?


A trapezoid is a rhombus.

A trapezoid is a parallelogram.

A trapezoid is a quadrilateral.

A trapezoid is a rectangle.

Answers

Answer:

„A trapezoid is a quadrilateral.” ⇒ true

Step-by-step explanation:

This is a trapezoid. It is a quadrilateral with one pair of parallel sides while other sides are non-parallel. Here, the opposite angles are alternate, that is, they have together 180°.

Isosceles trapezoid

An isosceles trapezoid is a trapezoid with congruent base angles and congruent non-parallel sides. Here, the base angles are the same.

The line segment joining the midpoints of the parallel sides is perpendicular to the bases and the diagonals are the same in length.

Right-angled trapezoid

Trapezoid with two right angles and necongruent non-paralell sides.

Good luck:)

Find the measure of angle A.
54.99
35.1°
50.7°
39.3°

Answers

Hi there!

[tex]\large\boxed{35.1^o}}[/tex]

We can once again use right triangle trig:

We are given the hypotenuse and adjacent sides, so cosine must be used:

cosA = A / H

thus:

cosA = 9/11

Use inverse trig to solve:

cos⁻¹(9/11) ≈ 35.1°

# If two vectors whose direction ratios are 1,2,3 and -k,2,1 are perpendicular to each other then, a) k=7 b) k=4 c) k=3 O d) k=6 me especially since we had be 1 poir 82) I don't know why he turned friends for so long.​

Answers

Answer:

(a)k=7

Step-by-step explanation:

We are given that

Two vectors whose direction ratios are 1,2,3 and -k,2,1.

Let

[tex]a_1=1,b_1=2,c_1=3[/tex]

[tex]a_2=-k,b_2=2,c_2=1[/tex]

We have to find the value of k.

We are given that two vectors are perpendicular to each other.

We know that two vectors are perpendicular to each other then

[tex]a_1a_2+b_1b_2+c_1c_2=0[/tex]

Substitute the values

[tex]1(-k)+2(2)+3(1)=0[/tex]

[tex]-k+4+3=0[/tex]

[tex]-k+7=0[/tex]

[tex]\implies k=7[/tex]

Hence, option a is correct.

PLEASE ANSWER IT CORECTLY

Answers

Answer:

Q24=A

25=B

26=A

Step-by-step explanation:

he area of a rectangle is 44m , and the length of the rectangle is less than twice the width. Find the dimensions of the rectangle.

Answers

Answer:

4m x 11m

Step-by-step explanation:

4 is your width. 11 is your length.

4 x 4=16 > 11

Johnny asks you to guess the specific coins he has in his pocket if he has $3.70 in change. You say you need a little
more information, to guess. So he tells you all he has is quarters and dimes and that he has 22 colns in all.

Answers

Answer:

10 quarters and 12 dimes :)

Step-by-step explanation:

F= P(1 + r)!
Rearrange the formula to highlight the present value.
P=

Answers

[tex]\tt\displaystyle\ P(1+r)!= r*(r-1) *(r-2)*(r-3) ..... *1[/tex]

For 12-15, find the missing measures

Answers

Answer:

12. d= 14, C=14π, A=49π

13. r= 13, d=26, A=169π

14. r=9, C=18π, A=81π

15. r=10, d=20, C=20π

Step-by-step explanation:

(9-3)+18÷8
show your work ​

Answers

Answer:

(9-3)+18÷8

=6+ 9/4

Step-by-step explanation:

.............

Answer:

8.25

Step-by-step explanation:

(9-3) + 18 ÷ 8

6 + 18 ÷ 8

6 + 2.25

8.25

I hope it helps ^_^

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