Please Help
Which two options describles physical properties of matter?
A. a substance's pH
B. a substance's resistance to flow
C. a substance's ability to conduct electricity
D. whether a substance rusts
E. a substance's inability to combine with other substances​

Answers

Answer 1

The correct options that describe the physical properties of matter are "A substance's resistance to flow," and "A substance's ability to conduct electricity." The correct options are B and C.

What is the physical properties of matter?

Physical properties of matter are characteristics that can be observed or measured without changing the substance's identity. These properties can help us identify and classify different substances.

Here in the Question,

Let's consider each option one by one:

A. A substance's pH is a chemical property of matter, which indicates whether a substance is acidic, neutral, or basic. It depends on the substance's chemical composition and the concentration of hydrogen ions in it. Therefore, this option is not a physical property.

B. A substance's resistance to flow is a physical property, also known as viscosity. It refers to how easily a substance can flow or be poured. For example, honey has a high viscosity, while water has a low viscosity. This property depends on the intermolecular forces between the molecules of the substance, which affect how closely they pack together. Therefore, this option is a physical property.

C. A substance's ability to conduct electricity is a physical property that depends on its structure and the presence of charged particles, such as ions or electrons. Substances that can conduct electricity are called conductors, while those that cannot are called insulators. Metals are good conductors of electricity, while plastics are good insulators. Therefore, this option is also a physical property.

D. Whether a substance rusts is a chemical property that indicates how a substance reacts with other substances, specifically with oxygen. Rusting occurs when iron or steel reacts with oxygen in the presence of water, forming a reddish-brown compound called iron oxide. Therefore, this option is not a physical property.

E. A substance's inability to combine with other substances is also a chemical property that depends on the substance's reactivity. Inability to combine with other substances may be due to a substance's stable electronic configuration, such as noble gases. Therefore, this option is also not a physical property.

Therefore, options B and C are true.

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Related Questions

A man is standing on the edge of a 20.0 m high cliff. He throws a rock horizontally with an initial velocity of 10.0 m/s. How long does it take to reach the ground? How far does the rock land from the base of the cliff?

Answers

Answer:

d = 20.2 m

t = 2.02 s

Explanation:

Horizontal Motion

When an object is thrown horizontally with a speed v from a height h, it describes a curved path ruled by gravity until it hits the ground.

To calculate the time the object takes to hit the ground, we use the equation:

[tex]\displaystyle t=\sqrt{\frac{2h}{g}}[/tex]

Note the time does not depend on the initial speed.

The range or maximum horizontal distance traveled by the object can be calculated as follows:

[tex]\displaystyle d=v.t[/tex]

The man standing on the edge of the h=20 m cliff throws a rock with a horizontal speed of v=10 m/s.

The time taken by the rock to reach the ground is:

[tex]\displaystyle t=\sqrt{\frac{2*20}{9.8}}[/tex]

[tex]\displaystyle t=\sqrt{4.0816}[/tex]

t = 2.02 s

Now for the horizontal range:

[tex]\displaystyle d=10\cdot 2.02[/tex]

d = 20.2 m

D 20202 hhsbdhhdhdhdhdhhs

Suppose the green car was traveling at 0 miles the white car was traveling at 70 miles at the red car was trailing at 22 miles which car is covering the most distance every second?

Answers

Answer:

The white car will cover the most distance every second.

Explanation:

The formula for the uniform speed of an object is given as follows:

[tex]s = vt[/tex]

where,

s = distance covered by the object

v = speed of the object

t = time required

Now, if we assume time to be  constant at 1 s. Then the distance covered by each car will be directly proportional to the speed of the car. Hence, the car with the greatest speed will travel the greatest distance in 1 second.

We, have:

Speed of white car > Speed of red car > Speed of green car

Therefore, the white car will cover the most distance every second.

All of the following are types of models EXCEPT
O a theory.
Dan analogy.
Oa physical replica.
O a mathematical representation.

Answers

The fist answer is correct the send on is correct and the third one is correct he fourth one is incorrectly

Answer:

A theory

Explanation:

No, the person who answered above is incorrect. I just took the assessment and I can guarantee you the answer is "a theory".

-Lexi

 If you drive your 1,000 kg car from sea level up to the mountain, which is 366 m above sea level, how much will you have increased your car's potential energy?(consider : g=10m/s2) *

1 point

a) 366,000 J

b) 3,660,000 J

c) 2.73 J

d) 20.73 J​

Answers

Answer:

Option B. 3660000 J

Explanation:

At the sea level, we'll assume that the height is 0 m. Hence, the potential energy at the sea level is zero.

Next, we shall determine the potential energy at a height of 366 m above the sea level. This can be obtained as follow:

Mass (m) = 1000 kg

Acceleration due to gravity (g) = 10 m/s²

Height (h) = 366 m

Potential energy (PE) =?

PE = mgh

PE = 1000 × 10 × 366

PE = 3660000 J

From the calculations made above, we can see clearly that the potential energy of the car at a height of 366 m above sea level is 3660000 J.

Hence, the potential energy of the car increases from 0 at the sea level to 3660000 J at 366 m above the sea level.

What do atoms of elements in a group have that makes their properties similar? A. the same atomic mass
B. the same number of protons
C. the same number of outer level electrons
D. the same total number of electrons

Answers

Wait I think i have the same assignment as you I put C.

20 n west and 60 n east

BLANK 1: What is the net force acting on the object

BLANK 2: Which direction will the object move​

Answers

Answer:

a) [tex] F_{T} = 40 N [/tex]

b) The object will move in the east direction

Explanation:

a) The net force is given by the vector sum of the given forces:

[tex] F_{T} = F_{1} + F_{2} [/tex]

Where:

F₁ = the west force = 20 N

F₂ = the est force = 60 N  

Taking the east direction as the positive direction we have:

[tex] F_{T} = -20 N + 60 N = 40 N [/tex]

Hence, the net force is 40 N.

b) Since the east force is greater than the west force, the object will move to the east.

I hope it helps you!  

define relative velocity​

Answers

Cccddydjddbfhfjjdhhdbhjff

El motor de una licuadora gira a 3600 rpm, disminuye su velocidad angular hasta 2000 rpm realizando 120 vueltas. Calcular: a) La aceleración angular b) El tiempo transcurrido

Answers

Answer:

a) α = -65,2 rad/s².

b) t = 2,57 s.

Explanation:

a) La aceleración angular se puede calcular usando la siguiente ecuación:

[tex] \omega_{f}^{2} = \omega_{0}^{2} + 2\alpha \theta [/tex]

En donde:

[tex]\omega_{f}[/tex]: es la velocidad angular final =  2000 rpm = 209,4 rad/s

[tex]\omega_{0}[/tex]: es la velocidad angular inicial = 3600 rpm = 377,0 rad/s

α: es la aceleración angular=?

θ: es el desplazamiento o número de vueltas = 120 rev = 754,0 rad

Las conversiones de unidades se hicieron sabiendo que 1 revolución = 2π radianes y que 1 minuto = 60 segundos.  

Resolviendo la ecuación (1) para α, tenemos:

[tex]\alpha = \frac{\omega_{f}^{2} - \omega_{0}^{2}}{2\theta} = \frac{(209,4 rad/s)^{2} - (377,0 rad/s)^{2}}{2*754,0 rad} = -65,2 rad/s^{2}[/tex]  

Entonces, la aceleración angular es -65,2 rad/s². El signo negativo se debe a que el motor está desacelerando.  

b) El tiempo transcurrido se puede encontrar como sigue:

[tex] \omega_{f} = \omega_{0} + \alpha t [/tex]

Resolviendo para t, tenemos:

[tex]t = \frac{\omega_{f} - \omega_{0}}{\alpha} = \frac{209,4 rad/s - 377,0 rad/s}{-65,3 rad/s^{2}} = 2,57 s[/tex]

Por lo tanto, el tiempo transcurrido fue 2,57 s.

Espero que te sea de utilidad!

A surface has the area vector A = (10i + 8j) m2. Find the flux of a uniform electric field through the area if the field is E = 7i N/C

Answers

Answer:

The value is [tex]\phi = 70 N\dot m^2 / C[/tex]

Explanation:

From the question we are told that

     The area vector is  [tex]\vec A = (10i + 8j) \ m^2[/tex]

     The  electric field is  [tex]E = 7 i \ N/C[/tex]

Generally the flux is  mathematically represented as  

        [tex]\phi = \vec E * \vec A[/tex]

=>      [tex]\phi = 7i * ( 10 \ i + 8 \ j )[/tex]

=>       [tex]\phi = (7 * 10 )\ i[/tex]  

Note  [tex]i \cdot j = 0[/tex]

=>      [tex]\phi = 70 N\dot m^2 / C[/tex]

1. Explain why a piece of white paper looks green when viewed through a piece of green plastic?

Answers

Answer:

because the light is refracted and slowed down to make us see the color "green"  and the things we see..like paper..the color "green" A white sheet of paper reflects almost all the light that falls on it. It reflects white light because it can reflect all the colors of the spectrum that comprise white light. If red light only is shone onto a white page, the red light is reflected. If the green light is shone onto the page, the green light is reflected.

Explanation:

hope this helps?

Answer:

the wave length that are reflected  determine the color  that an object appears  to the human eye. for example,the leaves appear green because  they reflect green light and absorb light of other  wavelengths.This means that  the light passes through the material rather than being reflected by it.

Explanation:

audeze oriented physics professor drives 3.25 km North than 4.75 km west and then 15 km South find the magnitude and direction of the resultant vector ​

Answers

Answer:

first lets do the anti parralel part of forces

we get 18. 25-15 =3.25 to north

then ww use phytagores theorem

3.25^2+4.75^2=c(resultant )

10.56+22.56=33.12

square root of 33.12 is 5.75

Find the acceleration if the force is 10,000 N and the mass is 500 kg.

Answers

Answer:

20m/s²

Explanation:

Given parameters:

Force  = 10000N

Mass  = 500kg

Unknown:

Acceleration  = ?

Solution:

According to Newton's second law of motion:

     Force  = mass x acceleration

Mass is the amount of matter in a substance

Acceleration is the rate of change of velocity with time

 Now insert the parameters and solve;

           10000 = 500 x acceleration

            Acceleration  = 20m/s²

True of False, in physics the term weight and force of gravity have the
same meaning?"
Help with both questions please.

Answers

Answer:

1) True

2) None of the above

Explanation:

Q # 1:

Weight is actually the gravitational force or force of gravity. So, it's true.

Q # 2:

None of above because force of gravity can not be negative. In order to have a negative weight, the body has to be "repelled" by gravity.

[tex]\rule[225]{225}{2}[/tex]

Hope this helped!

~AH1807
first one is true and none of the above for the second one

Calculate the pressure in pascals if a 650N force is applied to an area of 6.5m².

Answers

Answer:

100 Pa

Explanation:

650 ÷ 6.5 = 100 ( Pa )

Force=650NArea=6.5m^2

[tex]\\ \sf\longmapsto Pressure=\dfrac{Force}{Area}[/tex]

[tex]\\ \sf\longmapsto Pressure=\dfrac{650}{6.5}[/tex]

[tex]\\ \sf\longmapsto Pressure=100Pa[/tex]

What does the slope on a velocity-time graph measure?

Answers

Answer:The slope in the velocity-time graph represents the acceleration. The slope is defined as the ratio of change in y-axis to change in the x-axis. The slope is represented by the letter m and following is the general formula used for determining the slope:

Explanation:

The slope of a velocity graph represents the acceleration of the object. So, the value of the slope at a particular time represents the acceleration of the object at that instant.

is that what it’s asking?

A bicyclist is finishing his repair of a flat tire when a friend rides by with a constant speed of 3.5 m>s. Two seconds later the bicyclist hops on his bike and accelerates at 2.4 m>s2 until he catches his friend. (a) How much time does it take until he catches his friend

Answers

Answer:

4.28 s

Explanation:

after two seconds (2 s) His friends is

d = 3.5 m/s x 2 s = 7 meter ahead.

in this state, a bicylist start from initial velocity vo = 0 m/s and accelerat 2.4 m/s²

then, when bicylist reach his friend

t friend = t bicyclist = t

d bicylist = d friend + d

-------

d friend = 3.5 . t

d bicylist = vo . t + ½ a t²

d friend + d = vo . t + ½ a t²

3.5 t + 7 = 0 . t + ½ . 2.4 . t²

3.5 t + 7 = 1.2 t²

0 = 1.2 t² - 3.5 t - 7

t = -1.363 and t = 4.28

take the positive one

A student kicks a ball of 1 kg with a velocity of 13ms. The contact is 0.2 sec. Find the force

Answers

Answer:

65 N

Explanation:

Assuming that the ball was at rest hence initial momentum = 0

Final momentum = mv = 1Kg × 13 ms-1 = 13 kgms-1

But

Ft= mv according to Newton's law

F= mv/t

F= 13kgms-1/0.2s

F= 65 N

Answer:

65 N

Explanation:

Given that :

Mass of ball = 1kg

Velocity = 13m/s

Time = 2 seconds

Using the relation :

Force = (mass * change in velocity) / time

The change in momentum of the ball :

Momentum = mass * change in velocity

Velocity change = (13 - 0) ; Given that initial velocity = 0 (at rest)

Momentum = 1kg * 13m/s

Momentum = 13 kgm/s

Therefore, the force, F equals;

F = change in momentum / time

F = 13kgm/s ÷ 0.2 s

Hence, Force, F = 65N

The product of an object's mass and its velocity.
A.Momentum
B.Force
C.Velocity
D.Speed

Answers

Aunswer : Momentum
(As) Definition of momentum: Product of mass and velocity is called Momentum.

A metal has 4000kg in the volume of 2m3. what is its density​

Answers

Answer:

2000 kg/m³

Explanation:

The density of a substance can be found by using the formula

[tex]density = \frac{mass}{volume} \\[/tex]

From the question we have

[tex]density = \frac{4000}{2} = 2000 \\ [/tex]

We have the final answer as

2000 kg/m³

Hope this helps you

Define relative motion??​

Answers

Answer:

The laws of physics which apply when you are at rest on the earth also apply when you are in any reference frame which is moving at a constant velocity with respect to the earth. For example, you can toss and catch a ball in a moving bus if the motion is in a straight line at constant speed.

Explanation:

A person who normally weighs 700 N is riding in an elevator that is moving upward but slowing down at a steady rate. If this person is standing on a bathroom scale inside the elevator, what would the scale read?

Answers

Answer:

The scale will read less than 700 N

Explanation:

Given;

normal weight of the person, W = 700 N

The upward acceleration of the elevator is given by Newton's second law of motion;

F = ma

Also, the weight of the person, W = mg

Net force on the person when the elevator accelerates upward is given as;

R = ma + mg

When the elevator slows down at a steady rate, then net force on the person is given as;

R = mg - ma

R = m(g - a), this net force on the person is also the reading of the scale.

Thus, the scale will read less than 700 N.

Answer: The answer is less than 700 N

A truck weighs 500 N on Earth. What's the mass of the truck?
O 5 Kg
O 50 Kg
500 kg
500 N
PLEASE HURRY

Answers

The answer is 50 kg plz mark as brainliest

Answer:

Solution given:

Wight [W]=500N

gravity [g]=10m/s²

mass[m]=?

we have

W=mg

500=m*10

m=500/10

m=50kg

the mass of the truck is 50kg.

Uses of lens and mirror in daily life

Answers

Answer:

Decorating. Because mirrors reflect light, they create an illusion of open space by doubling whatever is in a room. ...

Safety. People use mirrors and lenses for safety. ...

Vision. Eye doctors use lenses to correct vision. ...

Magnification and Science. ...

Energy and Affirmation Techniques. ...

Photography. ...

How does an increase in thermal energy affect the particle motion in each state of matter?

Answers

Answer:

Explanation:

A rise in temperature increases the kinetic energy and speed of particles; it does not weaken the forces between them. The particles in solids vibrate about fixed positions; even at very low temperatures. Individual particles in liquids and gases have no fixed positions and move chaotically.

A cyclist accelerates from a velocity of 10 miles/hour east until reaching a velocity of 20 miles/hour east in 5 seconds. What was the cyclist's acceleration?

Answers

Answer:

[tex]a = 0.894\ m/s^2[/tex]

Explanation:

Motion with Constant Acceleration

A body moves with constant acceleration when the speed changes uniformly in time. The equation used to find the final speed vf is

[tex]v_f=v_o+at[/tex]

Where vo is the initial speed, a is the acceleration, and t is the time.

The cyclist has an initial speed of vo=10 miles/hour and ends up at vf=20 miles/hour in t=5 seconds.

Both speeds are given in miles/hour and we must convert it to m/s:

1 mile/hour = 0.44704 m/s

10 mile/hour = 4.47 m/s

20 mile/hour = 8.94 m/s

The acceleration is calculated by solving for a:

[tex]\displaystyle a=\frac{v_f-v_o}{t}[/tex]

[tex]\displaystyle a=\frac{8.94-4.47}{5}[/tex]

[tex]a = 0.894\ m/s^2[/tex]

A car is traveling at an average speed of 120km/h.how long will it take to travel between two station 525km apart?​

Answers

Answer:

Time taken 4 hrs. 38 minutes

Explanation:

As speed = distance/time interval

So time taken = 4.38

speed=distance/time

we know the speed and we know the distance so we can calculate the time

120km/h=525km/time

time=525km/120km/h=4.375hours or 4 hours and 22 minutes and 30 seconds

What is S.I units? ​

Answers

Answer:

Explanation:

he SI rests on a foundation of seven (7) defining constants: the cesium hyperfine splitting frequency, the speed of light in vacuum, the Planck constant, the elementary charge (i.e. the charge on a proton), the Boltzmann constant, the Avogadro constant, and the luminous efficacy of a specified monochromatic source. Definitions of all seven (7) SI base units are expressed using an explicit-constant formulation and experimentally realized using a specific mises en pratique (practical technique).

The seven SI base units, which are comprised of:

Length - meter (m)

Time - second (s)

Amount of substance - mole (mole)

Electric current - ampere (A)

Temperature - kelvin (K)

Luminous intensity - candela (cd)

Mass - kilogram (kg)

The International System of Units (SI), commonly known as the metric system, is the international standard for measurement. The International Treaty of the Meter was signed in Paris on May 20, 1875 by seventeen countries, including the United States and is now celebrated around the globe as World Metrology Day. NIST provides official U.S. representation in the various international bodies established by the Meter Convention: CGPM - General Conference on Weights and Measures; CIPM - International Committee for Weights and Measures; and BIPM - The International Bureau of Weights and Measures.

The SI is made up of 7 base units that define the 22 derived units with special names and symbols. The SI plays an essential role in international commerce and is commonly used in scientific and technological research and development. Learn more about the SI in NIST SP 330 and SP 811.

Resources for Students and Teachers

Redefining the SI – In November 2018, the world’s measurement experts voted and unanimously approved a revision of the SI that establishes a measurement system entirely based on physical constants of nature. The changes became effective on World Metrology Day, May 20, 2019. (NIST)

Learn more about the Road to the Revised SI. Learn more about the SI Redefinition.(NIST)

The Last Artifact documentary and companion Grade 5 to 12 educational resources, which document the work that went on behind the scenes to modernize the International System of Units (SI). (Montana PBS)

NIST SP 1247 SI Base Units Relationships Poster – a colorful poster illustrating the relationships of the International System of Units (SI) derived units with special names and symbols and the seven traditional base units. (NIST)

Metric Trivia Quiz – How much do you know about the metric system (SI)? Try the NIST Metric Trivia Quiz online or use the Alexa skill to test your knowledge and be on your way to thinking metric! (NIST)

SI Education and Training – Explore NIST metric system education resources that build SI measurement system familiarity and fluency. (NIST)

Kids Education Resources. (NIST)

Busting Myths about the Metric System. (NIST Taking Measure Blog)

Resources

Becoming Familiar with SI

Everyday Estimation

Metrication FAQs

Prefixes

SI Publications

Understanding Metric

Writing with Metric Units

Answer:

International System of Units??

a group of interacting parts that move or work together

Answers

Answer:

A system is a group of interrelated interacting, or interdependent parts that for a complex whole. A system is a group of interrelated interacting, or interdependent parts that for a complex whole.

Explanation: Hope this helps ;)

What force is required to give an object with mass 50 kg an acceleration of 8 m/s2 O A. 6.25 N O B. 58 N O C, 400 N O D, 250 N​

Answers

Answer:

C, 400 N

Explanation:

Given parameters:

Mass of object  = 50kg

Acceleration  = 8m/s²

Unknown:

Amount of force  = ?

Solution:

According to Newton's second law of motion;

       Force  = m a

m is the mass

a is the acceleration

 Now insert the parameters and solve;

   Force  = 50  x  8  = 400N

In the middle of a turn, you should _____________________. A. brake hard to maintain complete control over your vehicle B. accelerate abruptly and straighten the wheel C. avoid using your brake or clutch, unless it is necessary to do so in order to avoid a collision D. downshift to allow you to turn more sharply

Answers

Answer:

D. Downshift to allow you to turn more sharply

D. downshift to allow you to turn more sharply

What is the purpose of downshifting?

The purpose of "downshifting", or shifting the transmission down from a higher gear to a lower gear, is so that a driver can accelerate their car as fast as possible when exiting a corner that they had to slow down for.

The reason for ensuring your downshift is completed before turning into the corner is because letting the clutch out and engaging a lower gear while turning can cause the car to spin.

Two special conditions where you should downshift

Before Starting Down a Hill.

Slow down and shift down to a speed that you can control without using the brakes hard. Otherwise the brakes can overheat and lose their braking power.

Before Entering a Curve.

Slow down to a safe speed, and downshift to the right gear before entering the curve. This lets you use some power through the curve to help the vehicle be more stable while turning. It also allows you speed up as soon as you are out of the curve.

Therefore,

In the middle of a turn, you should downshift to allow you to turn more sharply .

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albexa ko nepali aartha Read Shakespeare's "Sonnet 100What is the central idea of the sonnet?Where art thou, Muse, that thou forget'st so longOThe speaker considers his love to be his museTo speak of that which gives thee all thy might?The speaker wants his muse to help himimmortalize his love.The speaker fears that his love is growing old fasterthan he would likeThe speaker thinks that his muse is forgetful andlazy and wastes a lot of timeSpend'st thou thy fury on some worthless song,Darkening thy power to lend base subjects light?Return, forgetful Muse, and straight redeemIn gentle numbers time so idly spent;Sing to the ear that doth thy lays esteemAnd gives thy pen both skill and argumentRise, resty Muse, my love's sweet face surveyIf Time have any wrinkle graven there1f any be a satire to decay,And make Time's spoils despised every whereGive my love fame faster than Time wastes life.So thou prevent'st his scy the and crooked knife Your cell phone provider charges a monthly fee of $19.50 for 200 minutes. You are also charged $.25 per minute for each minute over 200 minutes. Last month, your bill was $29.50. a. Let m represent the total number of minutes you used last month. Use the verbal model below to write an equation. Ill give you brainlest if you answer this correctly 1What is the solution to the system of linear equations graphed here?A (0,2)B (-2,-4)C) No SolutionD) (-2,2) A 24-year-old female comes into the emergency department complaining of severe abdominal pain on her left side. She is pale,and her abdomen is very tender and hard upon assessment. She states that she believes she is three months' pregnant. What should thenurse suspect? What is 9 times 9Its so hard Z-Z-Z-Z-ZAP! The sky cracks apart Spilling shards of light Over the landscape BOOM! Clouds roil overhead Soon the sky is a sea Filled with gray waves. what is the main idea for this poem Why does a chemical equation need to be balanced to support the law ofconservation of matter?A. It has to show that atoms of a single element cannot formdifferent compounds.B. It has to show that atoms cannot be created from nothing.C. It has to show how existing matter can be destroyed by a chemicalreaction.D. It has to show that the total amount of matter increases over time How would your life change if I stopped using plastic? Use your brain and imagine. Which of the following is NOT something that prevented African American from voting? A. literacy tests B. poll taxes C. family lineage D medical tests Read the dictionary entry.pathetic [puh-THEH-tic] adj.1. causing to feel pity2. relating to emotions3. inferior4. absurdRead the sentence.The kitten was so pathetic when he mewed that I had to pick him up and comfort him.Which dictionary definition best describes how the word "pathetic is used in this sentence?relating to emotionscausing to feel pityinferiorabsurd 50t-43=52t-81WHAT IS T? Earth's crustal bedrock at the Mid-Atlantic Ridge is. composed mostly of1. Basalt with a density of 2.7 g/cm32. basalt, with a density of 3.0 g/cm3. granite, with a density of 2.7 g/cm34.granite, with a density of 3.0 g/cm Which statement best describes how due process has been applied in Supreme Court rulings? List 20 things that happen as youth fades away What best describes the efforts of W.E.B. Du Bois? O A. He was a famous pilot who made the first solo flight across the Atlantic Ocean. B. He helped found the NAACP and promoted African American equality C. He was a poet who gained fame as the unofficial leader of the Harlem Renaissance. D. He was a strong believer in Black Nationalism and thought African American's could not achieve equality in the United States. What are the strengths and weakness of the American democracy? Erica is hiking down a mountain. She descends at a rate of 36 feet per hour. She began the descent at 10 a.M. And finished at 6 p.M. What was her change in elevation after two hours? Why does salt sprinkled on icy roads cause the ice to melt?