-9 + 6b = 6b - 4 how many solutions

Suppose that a spherical droplet of liquid evaporates at a rate that is proportional to its surface area: where V = volume (mm3

Alex

Answer:

V = 20.2969 mm^3 @ t = 10

r = 1.692 mm @ t = 10

Step-by-step explanation:

The solution to the first order ordinary differential equation:

$\frac{dV}{dt} = -kA$

Using Euler's method

$\frac{dVi}{dt} = -k *4pi*r^2_{i} = -k *4pi*(\frac {3 V_{i} }{4pi})^(2/3)\\ V_{i+1} = V'_{i} *h + V_{i} \\$

Where initial droplet volume is:

$V(0) = \frac{4pi}{3} * r(0)^3 = \frac{4pi}{3} * 2.5^3 = 65.45 mm^3$

Hence, the iterative solution will be as next:

i = 1, ti = 0, Vi = 65.45

$V'_{i} = -k *4pi*(\frac{3*65.45}{4pi})^(2/3) = -6.283\\V_{i+1} = 65.45-6.283*0.25 = 63.88$

i = 2, ti = 0.5, Vi = 63.88

$V'_{i} = -k *4pi*(\frac{3*63.88}{4pi})^(2/3) = -6.182\\V_{i+1} = 63.88-6.182*0.25 = 62.33$

i = 3, ti = 1, Vi = 62.33

$V'_{i} = -k *4pi*(\frac{3*62.33}{4pi})^(2/3) = -6.082\\V_{i+1} = 62.33-6.082*0.25 = 60.813$

We compute the next iterations in MATLAB (see attachment)

Volume @ t = 10 is = 20.2969

The droplet radius at t=10 mins

$r(10) = (\frac{3*20.2969}{4pi})^(2/3) = 1.692 mm\\$

The average change of droplet radius with time is:

Δr/Δt = $\frac{r(10) - r(0)}{10-0} = \frac{1.692 - 2.5}{10} = -0.0808 mm/min$

The value of the evaporation rate is close the value of k = 0.08 mm/min

Hence, the results are accurate and consistent!

5 0

4 years ago

Which problem would you use the following proportion to solve for?

Brrunno [24]

Answer:

B

Step-by-step explanation:

40/100 is equal to 40% so 24/x =40/100 means 24 is 40% of x

3 0

3 years ago

Tanya bought 8.05 yards of fleece fabric to make costumes for a school play. She needs 1.25 yards of fabric for each costume. Ho

juin [17]

Answer:

6

Step-by-step explanation:

8.05 divided by 1.25 is 6.44

6 0

3 years ago

What is m angle 1? 35° 40° 55° 70°

gizmo_the_mogwai [7]

9514 1404 393

Answer:

(b) 40°

Step-by-step explanation:

Angle x and the one marked 70° are alternate interior angles, so are congruent. The sum of the two base angles of the isosceles triangle is ...

x° +x° = 70° +70° = 140°

So, the remaining angle 1 in the triangle is ...

180° -140° = 40°

∠1 = 40°

5 0

3 years ago

Select the polynomial that is a perfect square trinomial.

alexdok [17]

Answer:

Option D. It's a perfect square trinomial.

Step-by-step explanation:

(a) 36x² - 4x + 16

= (6x)² - 2(2x) + (4)²

It's not a perfect square trinomial

(b) 16x² - 8x + 36

= (4x)² - 2x(4x) + (6)²

It's not a perfect square trinomial

(c) 25x² + 9x + 4

= (5x)² + 2 $(\frac{9}{2}x)$ + (2)²

It's not a perfect square trinomial

(d) 4x² + 20x + 25

= (2x)² + 2(10x) + (5)²

= (2x+5)²

It's a perfect square trinomial.

8 0

3 years ago

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