Answer:
Black holes are a class of astronomical objects that have undergone gravitational collapse, leaving behind spheroidal regions of space from which nothing can escape, not even light. Observational evidence indicates that almost every large galaxy has a supermassive black hole at its center.
Explanation:
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What is a proper directive for using a can of compressed air to clean a pc?
A swimming pool, 10.0 m by 4.0 m, is filled with water to a depth of 3.0 m at a temperature of 20.2°c. if the energy needed to raise the temperature of the water to 29.7°c is obtained from the combustion of methane (ch4), what volume of methane, measured at stp, must be burned? ∆hcombustion for ch4 = -891 kj/mol
You need to find the mass of water in the pool.
Find the volume (10 x 4 x 3) = 120 m3
Water has a density of 1000g/m3,so 120 m3 = 120 x 1000 = 120 000 kg
[delta]H = 4.187 x 120 000 x 3.4 (and the units will be kJ)You then use the heat of combustion knowing that each mole of methane releases 891 kJ of heat so if you divide 891 into the previous answer, you will get the number of moles of CH4
Answer:
119.69 kilo liter volume of methane measured at STP, must be burned.
Explanation:
Length of the pool= 10.0 m
Breadth of the pool = 4.0 m
Height upto which the pool will be filled= 3.0 m
Volume of the water in the pool = volume of the pool :
= 10.0 m × 4.0 m × 3.0 m = [tex]120.0 m^3[/tex]
Density water = [tex]997 kg/m^3[/tex]
Mass of the water(m) = [tex]Density \times volume =997 kg/m^3\times 120 m^3=119,640 kg[/tex]
Energy required to raise the temperature = Q
Mass of the water = m = 119,640 kg =[tex]119,640\times 1,000 g=119,640,000 g[/tex]
Specific heat of water ,c= 4.186 J/g °C
Change in temperature, [tex]\Delta T=29.7^oC-20.2^oC=9.5 ^oC[/tex]
[tex]Q=mc\Delta T[/tex]
[tex]Q=119,640,000 g\times 4.186J/g ^oC\times 9.5 ^oC[/tex]
[tex]Q = 476,113.36\times 10^4J=476,1133.6 kJ[/tex]
Heat required to raised the temperature is 476,1133.6 kJ.
Heat evolved when 1 mol of methane = -891 Kj
Number of moles of methane giving (- 476,1133.6) kJ of heat:
[tex]\frac{-476,1133.6 kJ.}{-891}=5,343.58 mol[/tex]
At STP, 1 mol occupies = 22.4 L
Then 5,343.58 mol will occupy :[tex]22.4\times 5,343.58 L=119,696.19 l=119.69 kilo liter[/tex]
119.69 kilo liter volume of methane measured at STP, must be burned.
in which of these reaction is energy released
all reactions
no reactions
endothermic
exothermic
The correct answer is D. Exothermic
Explanation:
One of the features used to classify reactions is whether energy is released or absorbed during them. In this way, when the reaction causes energy to be absorbed this is classified as endothermic; an example of this is when an ice cube melts because it absorbs heat from the environment. On the other hand, if energy is released, the reaction is exothermic; for example, fire releases heat, and therefore this reaction is exothermic. According to this, it can be concluded not all reactions release energy but only exothermic reactions.
What energy powers the star throughout its life?
How many significant figures does 1.362 + 25.2 have?
The correct answer is that 1.362 + 25.2 has 3 significant figures.
To determine the number of significant figures in the sum of two numbers, one must consider the precision of both numbers. The number 1.362 has four significant figures, while the number 25.2 has three significant figures.
When adding or subtracting numbers, the result should have the same number of decimal places as the number with the fewest decimal places. In this case, 25.2 has one decimal place, while 1.362 has three decimal places. Therefore, the sum should be rounded to one decimal place to match the least precise number.
Adding the two numbers gives:
[tex]\[ 1.362 + 25.2 = 26.562 \][/tex]
Now, we round the result to one decimal place, as 25.2 has one decimal place:
[tex]\[ 26.562 \approx 26.6 \][/tex]
The result, 26.6, has three significant figures: 2, 6, and the 6 in the tenths place. Thus, the sum 1.362 + 25.2 has 3 significant figures.
Robert uses a spring scale to measure force. what are the units of his measurement?
What's the energy before a student jumps off a bridge
Lauren wants to know which location in her apartment is best for growing African violets. She has three African violets. She puts one on the balcony, one by the kitchen window, and one on the mantel in the living room. Each plant has the same size pot and the same soil, and Lauren gives each plant the same amount of water. What are the dependent and independent variables? Your answer:
The dependent variable in Lauren's experiment is the growth of the African violets, and the independent variables are the locations of the plants. Other growth factors like watering, plant food, soil amount, and soil type should be controlled to ensure the experiment's accuracy.
Explanation:In Lauren's situation with the African violets, the dependent variable is the growth or health of the plants, since it is what she is observing and measuring in response to the different conditions. The independent variables are the locations where the plants are placed (balcony, kitchen window, mantel in the living room), as these are the conditions that Lauren is changing to see how they affect the growth of the African violets.
To have a controlled experiment, Lauren should keep other factors constant that may affect plant growth, such as the amount of water (which she is already controlling), the amount of plant food, the amount of soil, and the type of soil.
If Lauren's experiment were setup like Gary's - with a focus on the amount of sunshine - she might control for things like individual plant variation, soil temperature due to different colors of containers, water loss due to evaporation from the soil, and the effect of insects which may attack one set of plants but not another.
Com what is the difference between the interfaceid and the classid
On vacation, your 1200 kg car pulls a 540 kg trailer away from a stop light with an acceleration of 2.20 m/s2. (a) what is the net force exerted by the car on the trailer?
Which of the following force fields will deflect electron beams?
Magnetic
Electrical
Gravitational
Answer:
Electrons re deflected by both electrical and magnetic fields.
Explanation:
When an electron enters in magnetic field at any arbitrary angle Θ, the magnetic force experiences by electron is given by
[tex]F = q \times v\times B\times Sin\Theta[/tex]
So, electron experiences a force and deflects.
When an electron enters into electric field, the force experiences by the electron is given by
[tex]F = q \times E[/tex]
So, electron also experiences a force and deflects.
Which statement describes a force between charged particles?
1)Like charges repel each other.
2)Like charges attract each other.
3)Unlike charges repel each other
like charges repel each other
A student pushes a box with a total mass of 50 kg. What is the net force on the box if it accelerates 1.5 m/s
A. 51.5 N
B. 48.5 N
C. 75 N
D. 33.3 N
Answer:
Net force acting on the box is 75 N.
Explanation:
It is given that,
Mass of the box, m = 50 kg
Acceleration of the box, [tex]a=1.5\ m/s^2[/tex]
Let F is the net force acting on the box. It can be calculated using the Newton's second law of motion. According to this law the force acting on an object is equal to the product of mass and acceleration with which it is moving. Mathematically, it is given by :
[tex]F=m\times a[/tex]
[tex]F=50\ kg\times 1.5\ m/s^2[/tex]
F = 75 N
So, the net force acting on the box is 75 N. Hence, this is the required solution.
why do responsible consumers use credit and credit cards?
An object is moving with a constant velocity of 278 m/s. How long will it take it to travel 7500 m, using the formula Delta X=Vt+1/2at^2
During exercise, the amount of ____________ carried in the blood to the muscles increases. (3 points)
You would need oxygen because as your workout intensifies, your body needs more oxygen to be supplied to the muscles.
When approaching an intersection where the traffic signal is out you should?
If you're approaching an intersection where the traffic signal is out, treat it as a four-way stop. Come to a full stop and proceed when it's your turn and it's safe. Some laws require drivers to treat broken traffic signals as stop signs.
Explanation:When approaching an intersection where the traffic signal is out, you should treat the situation as you would a four-way stop. This means that you should make a full stop at the intersection and proceed only when it's your turn and it's safe to do so. This rule is in place to prevent accidents from occurring.
Many vehicles speed through intersections without regard to the posted speed limit, especially when traffic signals are out. However, state laws typically require drivers to think of broken traffic signals as stop signs. If two vehicles arrive at the intersection at the same time, the vehicle on the left should yield to the vehicle on the right.
Furthermore, if the intersection is busy and multiple vehicles are waiting to proceed, drivers should take turns going in the order in which they arrived at the intersection. This is essential for maintaining order and preventing accidents at intersections where the traffic signal is out.
Learn more about Traffic Rules here:https://brainly.com/question/35894294
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Which simple machines combine to make scissors?
A.
one lever and two wedges
B.
two levers and two wedges
C.
one inclined plane and two wedges
D.
two inclined planes and two wedges
Answer:
C.
one inclined plane and two wedges
Explanation:
A radio station's channel, such as 100.7 fm or 92.3 fm, is actually its frequency in megahertz (mhz), where 1mhz=106hz and 1hz=1sâ1. calculate the broadcast wavelength of the radio station 104.1 fm.
A girl pushes a cart to the left with 100-N force a boy pushes it to the right with a 50-N force. The net force extended on the cart is
Iceland is located on what type of plate boundary?
Scientists used to believe that the earth was the center of the universe. which invention was primarily responsible for obtaining evidence against this?
a.sextant
b.astrolabe
c.hubble telescope
d.optical telescope
If vx = 3 meters/second and vy = 4 meters/second, what is the magnitude of the resultant velocity?
Answer
5m/s
Explanation:
Resultant is defined as the single velocity/forces that balances all other velocities/forces acting on a body. It is also defined as the vector sum of the vectors acting on a body.
Given two vectors in the x and y direction i.e Vx = 3m/s Vy = 4m/s
The formula of the resultant of both vectors will be;
R²= Vx² + Vy²
Where R is the resultant vector
R²= 3²+4²
R²=9+16
R²=25
R=√25
R=5m/s
Therefore, the magnitude of the resultant velocity is 5m/s
Which equation shows the relationship between the Kelvin and Celsius temperature scales?
The relationship between the Kelvin and Celsius temperature scales is given by: [tex]\( K = ^\circ C + 273.15 \)[/tex], where[tex]\( K \)[/tex] is the temperature in Kelvin and [tex]\( ^\circ C \[/tex]) is in Celsius.
The equation relating the Kelvin and Celsius temperature scales is [tex]\( K = ^\circ C + 273.15 \).[/tex] In this equation, [tex]\( K \)[/tex] represents the temperature in Kelvin, and [tex]\( ^\circ C \)[/tex] represents the temperature in Celsius. The addition of 273.15 to the Celsius temperature converts it to the equivalent temperature in Kelvin. This conversion is necessary because the Kelvin scale is an absolute temperature scale, starting from absolute zero, where molecular motion ceases entirely.
Conversely, to convert a temperature from Kelvin to Celsius, one subtracts 273.15. This relationship is crucial in various scientific and engineering applications where temperatures need to be expressed in different units. For instance, in physics and chemistry, Kelvin is often used in thermodynamic calculations, while Celsius is more commonly used in everyday contexts.
This relationship stems from the definition of the Kelvin scale, where 0 K is defined as absolute zero, the theoretical lowest temperature possible, and the Celsius scale, where 0°C is defined as the freezing point of water at standard atmospheric pressure, and 100°C is defined as the boiling point of water at standard atmospheric pressure. The offset of 273.15 accounts for the difference between the two scales' zero points.
What is the velocity of a rocket that travels 9000 meters in 12.12 seconds
A net force acting on an object will always cause a change in the object's _________.
Final answer:
A net force acting on an object causes a change in the object's momentum, which is explained by Newton's second law. External forces can be visualized with a free-body diagram to determine the net force acting on an object.
Explanation:
A net force acting on an object will always cause a change in the object's momentum. According to Newton's second law of motion, the net force is proportional to the rate of change of momentum and is also equal to the mass of the object multiplied by its acceleration (F=ma). This means that when a net external force is applied to an object with mass, it will experience acceleration, and thus, a change in momentum. External forces acting on the object can be visualized using a free-body diagram to help determine the net force.
It's also important to differentiate between the concepts of mass and weight. Mass is the quantity of matter in an object, and weight is the gravitational force acting on that mass. When an external force is applied, including gravitational force, and there is no other force to counteract it, the object will undergo acceleration as per Newton's second law.
When plugged into a 120-v wall outlet, how much current is used by an electric blanket rated at 140 w?
According to Abraham Maslow’s hierarchy of needs, which is most basic?
Answer:
Maslow (1943, 1954) stated that people are motivated to achieve certain needs and that some needs take precedence over others. Our most basic need is for physical survival, and this will be the first thing that motivates our behavior. Once that level is fulfilled the next level up is what motivates us, and so on.
Explanation:
1. The variable of social structure that lays the broadest framework of social location is
a. race
b. culture
c. social class
d. status
Option B i.e Culture is the right and the correct answer.
Culture is the variable of social structure that lays the broadest framework of social location. On the other hand we see race, social class and social status divide people according to their color, income, occupation, education, preveliges etc.
Answer: culture
Explanation: culture is the way of life in term of religion, belief, behaviour peculiar to some certain group of people in a particular location which may be slightly different or differ greatly from another set of people in another location.
What happens when the dew point and the temperature are the same?