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2 years ago

You are looking at a yellow flower growing outside in the sunshine. Why does it look yellow?

Physics

1 answer:

Alchen [17]2 years ago

3 0

Answer:

It looks yellow because that is the only (major) color reflected.

Visible spectra is from about 4000-7000 Angstroms (10^-10 m).

Red are longer wavelengths and blue are the shorter wavelengths.

The Sodium doublet (yellow) occurs around 5900 Angstroms.

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How to find yield strength of a load vs deflection?

liraira [26]

Σ/ε
σ = F/A
ε = ΔL/L
F = force
A = area
L = lenght
ΔL = |old lenght - new lenght|

6 0

3 years ago

standing side by side, you and a friend step off a bridge and fall for 1.6s to the water below. your friend goes first, and you

Andrew [12]

(a) The distance will be more than 2.0 meters.

In fact, you starts your fall after your friend has already fallen 2.0 meters. This means that your friend has already accelerated for a while, therefore his velocity will be greater than yours. But this statement will be actually true for the entire fall, since you has some delay, therefore when your friend will hit the water, the separation between you and him will be greater than the initial separation of 2.0 meters.

b) First of all we need to calculate the height of the bridge with respect to the water. We know that you take 1.6 s to fall down, therefore we can use the following equation:

$S=\frac{1}{2}gt^2=\frac{1}{2}(9.81 m/s^2)(1.6s)^2=12.56 m$

We know that your friend will take 1.6 s to falls down. Instead, you start your jump after he has already fallen 2.0 m, therefore after a time given by the equation:

$S=\frac{1}{2}gt^2$

Using S=2.0 m,

$t=\sqrt{\frac{2S}{g}}=\sqrt{\frac{2(2.0 m)}{9.81 m/s^2}}=0.64 s$

So we know that you start your fall 0.64 s after your friend. Therefore, now we can find how much did you fall between the moment you started your fall (0.64 s) and the moment your friend hits the water (1.6 s). Using

$t=1.6 s-0.64 s=0.96 s$

we find

$S=\frac{1}{2}gt^2=\frac{1}{2}(9.81 m/s^2)(0.96 s)^2 =4.52 m$

So, when your friend hits the water, you just covered 4.52 m, while he already covered 12.56 m. Therefore, the separation between you and your friend is more than 2 meters.

8 0

4 years ago

You are riding a bicycle at 20 m/s at 10:00 am. At 10:01 am, you notice that you are traveling at 40 m/s. You are headed W. What

Juliette [100K]

Answer:

20m/s^2

Explanation:

Acceleration=Change in velocity/time taken for change

40-20/1

20m/s^2

7 0

3 years ago

PLS HELP ASAP!!! <br> I don’t understand this at all

Mnenie [13.5K]

Answer:

The part that completes the nuclear equation is:

$^{221}_{87}Fr$

Explanation:

<h2>A) Preliminar explanation</h2>

The <em>nuclear equation</em> represents a nuclear reaction: the change of the nucleus of an atom.

The given equation represents an actinium atom releasing an alpha particle.

This is the meaning of each part of the equation:

Ac is the chemical symbol of actinium
The superscript to the left of the chemical symbol is the mass number of the atom (number of protons plus number of neutrons). The mass number is 225.
The subscript to the left of the chemical symbol is the atomic number of the atom (number of protons). The atomic number is 89.

$^4_2He$ is the symbol of the alpha particle. It is an atom of helium
The mass number is 4
The atomic number is 2

<h2>B) Solution</h2>

To <em>complete the nuclear equation </em>you must do two balances: mass number balance and atomic number balance.

<u>i) Mass number balance</u>

225 = A + 4 ⇒ A = 225 - 4 = 221

<u>ii) Atomic number balance</u>

89 = Z + 2 ⇒ Z = 89 - 2 = 87

Therefore, the mass number of the unknown atom is 221, and the atomic number is 87.

From a periodic table, the element with atomic number 87 is francium, Fr.

Now, you have the chemical symbol, the atomic number, and the mass number of the unknown atom, which lets you to write the atom that completes the <em>nuclear equation</em>.

$^{221}_{87}Fr$

7 0

4 years ago

Recall that if a line is parallel to the vector v and passes through the point P0, which is the tip of the position vector r0, t

Elenna [48]

Answer:

The vector equation of the line is

$\overrightarrow{r}=+t$