Answer:
Consider the energy the earth receives from the sun. The electromagnetic waves travel thru empty space until they interact with some medium surrounding the earth: ozone, atmosphere, solids, etc.
This is contrasted to longitudinal waves such as sound waves which can only travel thru the medium with which they interact.
Để có 100 lít nước ở 370C. Người ta pha nước đang sôi với nước ở 150C. Tính thể tích nước mỗi loại cần dùng.Biết khối lượng riêng của nước là 1000kg/m3
Answer:
nước sôi: 440/17 l
nước 15°C:1260/17 l
the slope of a line on a position vs time graph is the
a. velocity
b. time
c. distance
d. displacement
It's the velocity, but only the magnitude. It can't show the direction of the velocity. So it's better to call it speed.
Indoor pollution experts conducted an analysis of the paint used in many office buildings which revealed that the paint contains traces of lead. The lead seems to rise to the surface of the paint and escape into the building's air supply. Tests show that because of the chemical drying process, the lead is not discernible on the surface until the paint has been on the walls for at least six months. To meet safety standards, owners should repaint walls at least every six months, or cover the walls with a different material.Which of the following, if true, would most weaken the conclusion above?A) The indoor pollution experts had no clear understanding of why it took six months for the lead to become discernible on the paint's surface.B) The indoor pollution experts neglected to examine the paint for traces of other toxic substances such as cadmium and mercury.C) The amount of lead found on the surface of the paint after six months remained constant for the next two years.D) The indoor pollution experts found that even in those offices painted with a different brand of paint, traces of lead were still found in the air workers breathed.E) The indoor pollution experts' research shows that the amounts of lead that come into contact with the air people breathe, even in the office buildings that used the greatest amount of paint, are too low to affect workers.
Answer:
E) The indoor pollution experts' research shows that the amounts of lead that come into contact with the air people breathe, even in the office buildings that used the greatest amount of paint, are too low to affect workers
Explanation:
The conclusion that would weaken the above statement if true was that the amount of lead found in air was not hazardous for the people living in building and the effects of such paint was quite low o affect workers.Luis rushes 40m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60s.
What is Luis’s average speed over the 60s?
What is Luis average velocity over the 60s?
1. The average speed of Luis over the 60 s is 1.33 m/s
2. The average velocity of Luis over the 60 s is zero.
1. The average speed can be calculated with the following equation:
[tex] S = \frac{d}{t} [/tex]
Where:
d: is the total distance traveled
t: is the total time = 60 s
The total distance can be calculated by the sum of the distance traveled to the truck (40 m) and the distance traveled to his home (the same 40 m), as follows:
[tex] d = 40 m + 40 m = 80 m [/tex]
So, the average speed is:
[tex] S = \frac{d}{t} = \frac{80 m}{60 s} = 1.33 m/s [/tex]
Hence, Luis's average speed over the 60 s is 1.33 m/s.
2. Now, the average velocity is a vector given by:
[tex]v = \frac{\Delta x}{\Delta t} = \frac{x_{f} - x_{i}}{t}[/tex]
Where:
[tex]x_{f}[/tex]: is the final distance traveled (the way to his home) = 40 m
[tex]x_{i}[/tex]: is the initial distance traveled (the way to his truck) = 40 m
Δt: is the total time = t = 60 s
Given that Luis in his journey, returns to the same starting point (his house), the total displacement is zero, and so the average velocity is also zero:
[tex]v = \frac{x_{f} - x_{i}}{t} = \frac{40 m - 40 m}{60 s} = 0[/tex]
Therefore, Luis's average velocity over the 60 s is zero.
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As shown in the figure below, Luis rushes 40 m toward his truck. He notices he forgot his shoes and returns back to his house. His total travel time is 60 s.
Answer:
What is Luis’s average velocity over the 60 s period?
Answer: 0 m/s
What is Luis’s average speed over the 60 s period?
Answer: 1.33 m/s
Difference between gravitational force and frictional
Explanation:
gravitational force or gravity is the force of attraction between objects that have mass.
frictional force is the forec that opposes motion (movement) when two surface are in contact. (acts in the opposite direction of motion)
so to sum it up,
- gravtional force is the force of attraction between objects that have mass.
- objects on the earth have weight because of gravitational force between them and the earth.
frictional force
- oppose motion
- slow down and stop moving objects and;
- produce heat
hope it helps :)
which two phenomena make up electromagnetism?
A) moving charges in an electric current attract each other
B) permanent magnets form a magnetic field from one pole to the other pole
C) an electric current causes a magnetic field around a core of magnetic metal
D) a moving magnet causes an electric current in a magnetic metal
Explanation:
the correct answer is option ( C ) and ( D )
why does apparent depth of different liquids vary
can ya pls answer dis!
Answer:
Here Is An OverView of What I Know About Science:
To understand what science is, just look around you. What do you see? Perhaps, your hand on the mouse, a computer screen, papers, ballpoint pens, the family cat, the sun shining through the window …. Science is, in one sense, our knowledge of all that — all the stuff that is in the universe: from the tiniest subatomic particles in a single atom of the metal in your computer's circuits, to the nuclear reactions that formed the immense ball of gas that is our sun, to the complex chemical interactions and electrical fluctuations within your own body that allow you to read and understand these words. But just as importantly, science is also a reliable process by which we learn about all that stuff in the universe. However, science is different from many other ways of learning because of the way it is done. Science relies on testing ideas with evidence gathered from the natural world. This website will help you learn more about science as a process of learning about the natural world and access the parts of science that affect your life.
Explanation:
Science helps satisfy the natural curiosity with which we are all born: why is the sky blue, how did the leopard get its spots, what is a solar eclipse? With science, we can answer such questions without resorting to magical explanations. And science can lead to technological advances, as well as helping us learn about enormously important and useful topics, such as our health, the environment, and natural hazards. Without science, the modern world would not be modern at all, and we still have much to learn. Millions of scientists all over the world are working to solve different parts of the puzzle of how the universe works, peering into its nooks and crannies, deploying their microscopes, telescopes, and other tools to unravel its secrets. I Hope This Helps.
Ploughing field with harrow pulled by a tractor is a modern technology
Ploughing field with harrow pulled by a tractor being a modern technology is true.
What is Technology?This involves the use of scientific knowledge to tackle different life problems and has different sectors.
Ploughing field with harrow pulled by a tractor involves machines and not manual labour which makes it a modern technology.
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How can you say gravitational force is a field force
Answer:
because gravity pulled us in the land if there is no gravitational force there will not be field force too
Explanation:
hope it's will help you
The density of a material in CGS system of units is 4g cm-³. In a system of units in which unit of length is 10 cm and unit of mass is 100g, the value of density of material will be...?
1) 0.04
2) 40
3) 0.4
4) 400
[tex]\sf\underline{Solution:}[/tex]
Here , the density of the material is 4g cm³ but it is not given in CGS system.
$\sf{As\:we\:know\:that:}$
$\sf\bold{Density=}$ $\sf\dfrac{Mass}{Volume}$
$\space$
[tex]\sf{Now,according \: to \:the\:question:}[/tex]
$\sf\small{Density\:of\:the\:material=4}$ $\sf\dfrac{g}{cm^2}$
$\space$
$\sf{It\:is\:given\:that:}$
In the system of units the mass is 100gram.
$\space$
Hence,
$\sf{The\:mass\:unit\:for\:4g=}$ $\sf\dfrac{4}{100}$ $\sf{units}$
$\space$
In the system of units,the length is 10cm.
Henceforth,
$\sf\small{The\:length \:for\:1cm\:units=}$ $\sf\dfrac{1}{10}$ $\sf{units}$
$\space$
☆ Substitute the required values in the given formula-
$\sf\purple{Density=}$ $\sf\dfrac\purple{Mass}\purple{volume}$
$\space$
$\sf\underline\bold{Density\:of\:the\:material:}$
= $\sf\dfrac{4/100}{1/10^3}$ $\sf\bold{units}$
$\space$
= $\sf\dfrac{4/100}{1/1000}$ $\sf\bold{units}$
$\space$
= $\sf\dfrac{4000}{100}$ $\sf\bold{units}$
$\space$
$\sf\underline\bold\blue{=40\:units}$
$\sf\small{Therefore,option\:2nd\:is\:correct!}$
_______________________________
A 4000 N force acts on an object that initially has a momentum of 400 kg-m/s for 0.9 seconds. What is the final momentum of the system?
Answer:
4360 Kgm/s
Explanation:
Applying,
Ft = M-M'................. Equation 1
Where F = force, t = time, M = Final momentum, M' = Initial momentum.
make M the subject of the equation
M = Ft+M'............ Equation 2
From the question,
Given: F = 4000 N, t = 0.9 seconds, M' = 400 kg-m/s
Substitute these values into equation 2
M = 4000+(0.9×400)
M = 4000+360
M = 4360 kgm/s
Hence the final momentum is 4360 kgm/s
Hess's law states that:
A. Energy cannot be created nor destroyed, it can only change form.
B. The enthalpy change when 1 mole of a substance undergoes complete combustion under standard conditions is equal to molar masses of the compounds.
C. When the enthalpy changes under standard conditions, 1 mole of a substance is formed from its elements.
D. The overall enthalpy change for a reaction is independent of the route the reaction takes.
Answer:
D. The overall enthalpy change for a reaction is independent of the route the reaction takes.
Answer: Hess's law states that the overall enthalpy change for a reaction is independent of the route the reaction takes. Option D is correct.
It is given Hess's law.
It is required to state the Hess's law.
What is Hess's law ?Thermochemical equations can be manipulated to give the data chemical reactions. We find exactly how much energy will be absorbed or released by the reaction because we may face various explosions.
There are mainly two ways to calculate ΔH of any reaction. First If the reaction has ΔH then the reverse of the reaction will have opposite ΔH and the second is if double the ΔH of the substances, double the ΔH.
Therefore Hess's law states that the overall enthalpy change for a reaction is independent of the route the reaction takes.
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A carnot engine has an efficiency of 50% when its sink temperature is 27°C. The temperature of source is: a) 300°C b) 327°C c) 273°C d) 373°C
327 degrees
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Why does a small piece of steel rod sinks while a large steel oil tanker floats?
Plss help thanks! pls include EXPLANATION and EXAMPLES that I can proof to people that has no knowledge
Answer:
Too what i know its because of the air
Explanation:
The steel rod is more dense and doesnt have air whil'st the oil tanker is less dense with lots of air
A large atomic bomb produces around 8.00x1015J of energy. How much matter does that bomb turn into energy?
A)2.67x10^79kg
B)2.67x10^7kg
C)7.20x10^32kg
D)0.0889kg
Answer:
D)0.0889kg
Explanation:
If a large atomic bomb produces around 8.00x10¹⁵J of energy, then from Einstein's energy law i.e E=mc² we can calculate that the amount of matter is 0.0889kg. The correct option is D.
What is Einstein's energy law?
The Einstein Energy Law, often referred to as Einstein's famous equation relates the energy of a particle (E) to its mass (m) and the speed of light (c). The equation is as follows:
E = mc²
This equation shows that energy (E) and mass (m) are equivalent and interchangeable and that a small amount of mass can be converted into a large amount of energy. This is the basis for understanding nuclear reactions and the energy released in processes like nuclear fusion and fission.
Here in the question,
To calculate the mass that is converted into energy in an 8.00x10¹⁵J nuclear reaction, we can rearrange the equation to solve for m:
m = E / c²
where c = 3 x 10⁸ m/s is the speed of light in a vacuum.
Substituting the values, we get:
m = 8.00x10¹⁵ J / (3 x 10⁸ m/s)²
m = 0.0889kg
Therefore, a large atomic bomb that produces around 8.00x10¹⁵ J of energy converts approximately 0.0889kg of matter into energy. This is a very small amount of matter, but because c² is such a large number, a huge amount of energy can be released from a small amount of matter in a nuclear reaction.
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A group of students are designing a field study to investigate the length of time a traffic light remains yellow.
Answer:
3 to 7 seconds.
Explanation:
According to the traffic engineers the length or the duration of the signal to turn form yellow or amber to green is more than 5 seconds. A time interval is needed to easy out the traffic flow.Given: F = k· m. g
Solve for "k"
Answer:
[tex]F = kmg \\ k = \frac{F}{mg} [/tex]
Explanation:
F = k . m . g
=> F = k . mg
[tex] = > k = \frac{F}{mg} (ans)[/tex]
a sphere of diameter 6.0
cm is moulded into a thin wire of diameter 0.2 mm calculate the length of the wire in metres
Answer:
V1 = 4/3 pi R^3 = pi D^3 / 6 D = 2 R volume of sphere
V2 = pi r^2 L = pi d^2 L / 4 volume of wire
V2 / V1 = 1 = 3/2 d^2 L / D^3 since volumes are equal
L = 2/3 D^3 / d^2 = 2/3 * 6^3 / .02^2 = 360,00 cm = 3600 m
How does modulus of elasticity change with the rise of temperature
Explanation:
With rise in temperature, the length of the material increases which decreases its stiffness. Thus, we can say that with rise in the temperature, the Young's modulus decreases.
What is conserved in a thermodynamically closed system?
A. Both energy nor matter
B. Energy
C. Both energy and matter
D. Matter
Explanation:
C. Both energy and matter
A city bus travels along its route from Jackson Street 8 km to Aurora Avenue, where it turns and continues 13 km.
What is the total distance that the bus has traveled? km
The total displacement of the bus is approximately 15 km northeast northwest southeast southwest.
im a bit confused on what the question is:(
if its just asking for the total number of km traveled it would be 21 km
Answer the following questions 1 What is the difference between mass and weight of an object. Will the mass and weight of an object on the earth be same as their values on Mars ? Why?
Answer:
difference between mass and weight is that mass is amount of matter in a material while weight is a measure of how the force of gravity acts upon that mass.the mass of an object will be same on earth and mars but its weight on both planets will be different.
How does a fuse work?
A. A material burns out when current is excessive
B. A material burns out when resistance is excessive
C. A material burns out when voltage is excessive
D. A material acts as a switch to prevent electricity from flowing when voltage is excessive
Answer:
A. a material burns out when current is excessive
Exercise b) 1) Fill in the blanks with the appropriate word: a) The pressure exerted by the air in atmosphere is called b) Pressure is the applied per unit area, c) The pressure ........as the depth of liquid increases. d) The SI unit of density is Az object fisats on water if the ...of the object is leva
Answer:
atmospheric pressure
b)
c)increases
d) ....
whats the beginning of life called
Answer:
Abiogenesis in evolutionary science, not sure about creation science
Explanation:
"Measurement is essential in our life. Justify the statement.
Explanation:
Measurement plays an important role in our daily lives because they are useful to do basic tasks, such as taking the temperature of a child with the help of a thermometer,making time estimations,measure out medicines and find out weights, areas and volumes of different substances
a teacher drives from school to the mall. then she goes to the doctors office for a physical examination. what is the magnitude of her displacement
The magnitude of the teachers displacement is the difference between
the location of the school and the location of the doctors office
The reason behind the above expression are explained as follows
The known locations of the teacher;
Initial location; The school
Second location; The mall
The eventual location; The doctors office
The required information;
The magnitude of the teachers displacement
The method of obtaining the displacement of the teacher;
Qualitatively, the displacement of the teacher can be obtained by applying the definition of displacement as follows;
The definition of displacement is an object's change in position, given by the difference between its start and finish locations
According to the definition of displacement, therefore, the magnitude of
the teachers displacement is the distance between the school and the
doctors office which is given by the difference between the coordinates of
the location of the school and the location of the doctors office
The magnitude of the displacement of the teacher = The coordinate of the location of the doctors office - The coordinate of the location of the school
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state the advantages and disadvantages of alkaline battery over a lead acid accumulator
Answer:
Alkaline batteries have longer shelf life than other batteries of the chloride type electrolyte batteries. They have a much higher energy density compared with other batteries. This allows the battery to produce the same energy while lasting longer than other batteries.
Advantage
1) Alkaline battery lasts long than other batteries
2) It have a much higher energy density
Disadvantage :
1) They are heavier and bulkier
2) They have high internal resistance
What is alkaline battery ?An alkaline battery is a type of primary battery that derives its energy from the reaction between zinc metal and manganese dioxide.
Advantage
Alkaline battery can produce same amount of energy by lasting longer than other batteries as it have longer shelf life than lead acid accumulator
Alkaline battery have a much higher energy density compared to lead acid accumulator
Disadvantage :
Alkaline battery are heavier and bulkier
Alkaline battery have high internal resistance
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what is required for force to come into play
Answer:
An interaction of one object with another object results in a force between the two objects. Thus, at-least two objects must interact for a force to come into play.
