According to the United Nations Environment Programme, hydropower accounted for 16.6% of global electricity generation in 2018.
This is equivalent to a total installed capacity of 706 GW, making it the second largest energy source after thermal sources.
Hydropower is a renewable energy source and is often seen as a more sustainable alternative to thermal sources, as it does not release any greenhouse gases into the atmosphere. Additionally, hydropower is a reliable source of energy, and can be used to meet peak energy demand.
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PLEASE HELP!!! Which phase change occurs when steam is cooled to 100°C?
condensation
boiling
sublimation
evaporation
The amount of energy needed to change a liquid into a gas, without changing its temperature, is known as the __________.
heat of sublimation
heat of fusion
specific heat
heat of vaporization
In which phase change are hydrogen bonds formed?
boiling
sublimation
evaporation
freezing
The specific heat of a substance is 0.215 J/g°C. How much energy is required to raise the temperature of 20 g of the substance from 72°C to 88°C?
68.8 J
323.4 J
4.3 J
3.4 J
The first question is asking which phase change occurs when steam is cooled to 100°C. The answer is condensation.
The second question is asking for the term that refers to the amount of energy needed to change a liquid into a gas, without changing its temperature. The answer is heat of vaporization.
The third question is asking in which phase change hydrogen bonds are formed. The answer is freezing.
The fourth question is asking for the amount of energy required to raise the temperature of 20 g of a substance from 72°C to 88°C, given that the specific heat of the substance is 0.215 J/g°C. To solve this problem, you can use the formula Q = m * c * delta T, where Q is the energy required, m is the mass of the substance, c is the specific heat, and delta T is the change in temperature. Plugging in the given values, you get Q = 20 g * 0.215 J/g°C * (88°C - 72°C) = 68.8 J. Therefore, the answer is 68.8 J.
During a magic trick, a magician twirled a ball on a string horizontally at a constant rate. He then doubled the length of the string but maintained the rate at which the ball rotated. Which of the following factors remained constant? A angular velocity B centripetal acceleration с centripetal force
Correct option is C, Centripetal force remains constant.
Centripetal Force -
Any force that changes the direction of motion toward the center of a circular motion is known as a centripetal force. The part of the force that produces the centripetal force is the part that is perpendicular to the velocity.
A net force that keeps an object moving in a circular motion is known as a centripetal force.
Centripetal force has the formula =mv2r. The newton or kgms2 is the measure of force.
A centripetal force is applied to any item travelling in a circle (or along a circular path). In other words, the object is being physically pushed or pulled in the direction of the circle's center. This is the necessary centripetal force.
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humans taste food mostly because of:
Answer:
taste buds
Explanation:
very sensitive microscopic hairs called microvilli. The tiny hairs send messages to the brain about how something tastes, so you know if it's sweet, sour, bitter, or salty
What details can you add to your model of sound? model being a slinky
Answer:
I really hope this helps
Explanation:
an object with mass m is dropped from rest, one model for its speed v after t seconds, taking air resistance into account, is
The required lim t → ∝ v(t) when an object is dropped from rest is calculated to be mg/c.
Given that,
An object with mass m is dropped from rest and taking air resistance into account.
The velocity as a function of time is,
v(t) = (m g)/c [ 1 - e^-(ct/m)]
v(t) = (m g)/c [ 1 - 1/e^(ct/m)]
lim t → ∝ v(t) = (m g)/c [ 1 - 1/∝]
lim t → ∝ v(t) = (m g)/c ( 1 - 0)
lim t → ∝ v(t) = (m g)/c
Thus, the required lim t → ∝ v(t) when an object is dropped from rest is calculated to be mg/c.
The question is incomplete. The complete question is 'v = mg c (1 − e−ct/m) where g is the acceleration due to gravity and c is a positive constant describing air resistance. (a) Calculate lim t→∞ v.'
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if the crumple zone exerts +200,000 N of force on the wall, how much force will the wall exert on the crumple zone?
Answer: -200,000N
(To be more specific, 200,000N in the opposite direction)
Explanation:
By Newton's 3rd law (Action reaction pair)
The crumple zone exerts a force on the wall, the wall will exert an equal but opposite force on the wall.
Same magnitude -> 200,000N
Opposite direction-> Include a negative sign as force is a vector which depends on both magnitude and direction.
A block-spring system vibrating on a frictionless, horizontal surface with an amplitude of 6.0 cm has a total energy of 12 J. If the block is replaced by one having twice the mass of the original block and the amplitude of the motion is again 6.0 cm, what is the energy of the more massive system
In this spring-mass system, the total energy equals the elastic potential energy at the moment the mass is temporarily at rest at x = A = 6 cm (i.e., at the extreme ends of the simple harmonic motion).
Thus, E kA2 2 and we see that as long as the spring constant k and the amplitude A remain unchanged,
the total energy is unchanged. Hence, the energy is still 12 J.
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Light demonstrates the characteristics of _______________. particles only waves only both photons and particles both waves and particles
Both the features of waves and particles can be seen in light.only photons and particles only photons and particles, only waves.
Photons are they both waves and particles?Both a wave as well as a particle description of light are possible.The dual character of light has been highlighted in particular by two investigations.When we consider that light is composed of tiny particles, we refer to those particles as "photons."
What are waves and particles both?The following is the image for 'photons & particles combining waves and particles'.While electromagnetic radiation behaves both like a wave and a particle at the same time, it propagates according to linear wave equations and can only be released or absorbed in discrete pieces.
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Two small objects carry the same amount of charge, and the magnitude of the electric force exerted by one object on the other is 0.10 N when they are held 30 mm apart. If the force magnitude increases when the objects are released and free to move, are the objects of the same charge or opposite charge?
The objects must be of opposite charge because the electric force of attraction between them increases when they are released and free to move.
This means that the electric force must be a repulsive force that pushes the objects away from each other. Opposite charges attract and as charges repel, the objects must be of opposite charge for the electric force to increase when the objects are released and free to move.
Therefore when two small objects carry the same amount of charge, the magnitude of the electric force exerted by one object on the other is 0.10 N when they are held 30 mm apart. If the force magnitude increases when the objects are released and free to move, then we can say that they are opposite charges.
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4. A railcar of mass m and speed v collides and sticks to another identical, stationary railcar. The speed of the center of mass of the two-railcar system will be
The required speed of the centre of mass of the two-railcar system after the collision will be half as much as it was before the collision.
One of the railroads has zero motion prior to the collision. Following it, both railroads move at the same speed. By the conservation of the total momentum of the system, we have,
m vi = m vf + m vf
m vi = 2 m vf
vi = 2 vf
vf = 1/2 vi
vf is the velocity after collision
vi is the velocity before collision
Thus, the speed of the railroad together after the collision is calculated to be half of that before collision.
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A boy exerts a force of 225 N on a lever (Links to an external site.) to raise a 1250 N rock a distance (Links to an external site.) of 0.13 m. If the lever is frictionless, how far did the boy have to move his end of the lever
If the lever is frictionless, to raise the rock a distance of 0.13 m, then the boy has to move the lever to 0.72 m.
An external force that acts upon an object results in a motion of the object, then it is called a work done upon the object by that force.
Given that the external force on a lever is 225 N and on a rock is 1250 N. The distance of motion by the rock is 0.13 m.
Hence the work done by the lever will be equivalent to the work done by the rock to move a particular distance.
Work (Lever) = Work (Rock)
F(lever) x D (lever) = F (rock) x D (rock)
225x D(lever)= 1250 x0.13
D(lever) is 0.72 m
Hence we can conclude that the distance of the motion by the lever is 0.72 m.
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A skier is pushed from the top of a hill so that he starts moving down the hillside from a height of 100 m with
an initial speed of 0.434 m/s. After traveling 80.4 m, he reaches the bottom of the valley. Due to inertia, he
then continues 70.4 m up another hillside (y = 40 m) and crashes into a snow bank that compressess like a
spring (k = 50 N/m). What is the skiers speed as he crashes into the snow bank? How far does the snow
compress? Assume that you can neglect friction.
Speed as the skier crashes into the snow bank: 0.434 m/s
Distance the snow compresses: 1.544 m
The speed of the skier as he crashes into the snow bank is the initial speed since there is no acceleration due to the lack of friction. The distance the snow compresses is calculated using the following equation:
compression = (mass x velocity2) / (2 x spring constant)
Therefore, compression = (75 kg x 0.4342) / (2 x 50 N/m) = 1.544 m
Gravity on the surface of the moon is only 1 6 as strong as gravity on the Earth. What is the weight of a 35 kg object on the Earth
Answer:
Weight of a 35kg object on Earth is 350N, while it is 56N on the Moon.
Explanation:
The conversion of mass (kg) to weight (N) on Earth is 1kg to 10N.
Thus, the weight of a 35kg mass on Earth is
35kg × 10 = 350N
On the Moon, conversion of mass to weight is 1kg to 1.6N.
Thus, the weight of a 35kg mass on the Moon is
35kg × 1.6 = 56N
Remember, mass remains constant regardless of location, while weight depends on the strength of the gravitational field.
Draw conclusions: Objects falling through air are slowed by the force of air resistance. Which objects were slowed the most by air resistance
Due to this air resistance, Galileo discovered that heavier or more dense things fall more quickly than less dense ones. Together, a brick and a feather fell. The feather falls more slowly due to air resistance.
Descending against air resistance an object often experiences some air resistance as it falls through the air. The leading surface of the object collides with air molecules, creating air resistance. Several variables affect how much air resistance the object really experiences.
Therefore, heavier things fall quicker than lighter ones because the force of gravity acting on them is greater. As a result, heavier objects accelerate at faster speeds until the force of air resistance acts on them.
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Select the correct answer. A boy is pushing a chair by applying a force of 5 newtons. His mother helps him push it faster by applying an additional force of 7 newtons in the same direction. What is the net force acting on the chair
Answer:
The net force is now 12
Explanation:
The boy is applying a force of 5 newtons + his mother is helping him to apply 7 newtons = 12 newtons.
When a rubber rod is rubbed with wool, the rod becomes negatively charged. What can you conclude about the magnitude of the wool's charge after the rubbing process
The wool must start out negatively charged before becoming positively charged after donating its electrons to the rubber rod.
What happens when wool is rubbed on a rubber rod?A rubber rod becomes negatively charged when wool is brushed against it, and the magnitude of the charge on the wool is equal to the charge on the rod. By applying the same amount of negative charge to the rod, the wool becomes positively charged.
Why does a polythene rod become negatively charged when it is brushed against wool?Electrons generate energy while rubbing a polythene rod with a duster because of the friction. When they have enough energy, electrons can escape from an atom and "rub off" onto a polythene rod.
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Calculate the rotational kinetic energy of a 12-kg motorcycle wheel if its angular velocity is 120 rad/s and its inner radius is 0.280 m and outer radius 0.330 m.
According to the question the rotational kinetic energy of a 12-kg motorcycle wheel is 809.14 J
What does rotational kinetic energy?The SI unit for rotational kinetic energy is the joule (J). The rotating kinetic energy formula has a similar structure to a translational kinetic energy equation. Kinetic energy is created by spinning objects around an axis. This type of energy is influenced by the object's mass, weight, and center of mass angle with respect to the axis.
Given data -
Mass = 12-kg
Angular velocity (ω) -120rad/s
inner radius = 0.280 m
outer radius = 0.330 m.
By using the formula
I = ½*M (r1² + r2²)
I = ½ *(12) * (0.2802 + 0.3302)
I = 1.1238 Kgm2
K.E = ½*Iω2
K.E = ½ * (1.1238)*(120)2
K.E = 809.14 J
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If an airplane were traveling westward with a thrust force of 450 N and there was a headwind (drag) of 200 N, what would the resulting net force be on the airplane
The net resultant force on the airplane, based on the data provided in the question, is 250 N.
How can the net force that results be calculated?Calculate the resultant force by deducting the larger force's size from of the smaller force's magnitude. The direction of the smaller force and the resulting force are identical. The resulting force is useful because it allows us to think about the several forces as as if they were one. To measure the effects of different forces on a thing, in other words.
Given data -
Thrust force = 450 N
headwind (drag) = 200 N
Net force = 450 - 200
Net force = 250 N.
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Select the correct answer. a heat engine has a cold reservoir of 250 k and a hot reservoir of 715 k. what is the maximum efficiency of the engine?
a. 65.0%
b. 60.8%
c. 73.6%
d. 58.6%
e. 69.1%
The maximum efficiency of the engine is a. 65.0%
The maximum efficiency of the heat engine is given by the Carnot efficiency, which is defined as:
Efficiency = (1 - (T cold / T hot)) * 100%
Where T cold is the temperature of the cold reservoir and T hot is the temperature of the hot reservoir.
Plugging in the given temperatures, we get:
Efficiency = (1 - (250 / 715)) * 100% = 65.0%.
So the answer is a. 65.0%.
So, using the temperatures given in the question:
Efficiency = 1 - (250 K/ 715 K) = 1 - 0.349 = 0.651 or 65.1%
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The set of spectral lines that we see in a star's spectrum depends on the star's (a) atomic structure. (b) chemical composition. (c) rotation rate.
The set of spectral lines that we see in a star's spectrum depends on the star's (b) chemical composition, (d) temperature.
The spectral lines of a star are determined by its chemical composition and temperature. These properties determine the number and type of atoms present in the star's atmosphere. Each type of atom has its own unique set of spectral lines, and the temperature of the star determines the energy level of the atoms, which affects the wavelengths of the spectral lines emitted. The rotation rate and atomic structure of a star do not affect the set of spectral lines we see in its spectrum.
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water can be thought of as a mass of moving particles what evidence supports this idea.
When temperature of water rises, it stats moving from higher to lower temperature area - this evidence supports that water can be thought of as a mass of moving particles .
What are the properties of liquid?The volume retention and conformity to the shape of a liquid's container are two of its most noticeable physical characteristics. When a liquid substance is poured into a container, it conforms to the shape of the container and will stay inside the container so long as the liquid state persists.
Water is a liquid. Hence, water can be thought of as a mass of moving particles.
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A car at rest with respect to a building can be in motion with respect to another observer. True/False. Please explain your answer
A rope of length L is attached to a support at point C. A person of mass m, sits on a ledge at position Aholding the other end of the rope so that its horizontal and taut, as shown above. The person then dropsoff the ledge and swings down the rope toward position B on the lower ledge where an object withmass m₂ is at rest. At position B the person grabs hold of the object and simultaneously lets go of therope. The person and object then land together in the lake at point D, which is a vertical distance Lbelow position B. Air resistance and mass of the rope are negligible. Derive expressions for each of thefollowing in terms of m₁, m₂, L, and g.
Insignificant are air resistance and rope mass. Point C on a support is where a rope of length L is fastened.
What is meant by mass?As a measure of inertia, which is a characteristic of all matter, mass is used in physics. Effectively, it is the resistance a body of matter offers to a change in its speed or position as a result of the application of a force. The change caused by an applied force is proportional to the mass of the body.The amount of matter that makes up any object or body is best referred to as its mass. All of the objects we perceive have mass. There is mass in objects like tables, chairs, beds, footballs, glasses, and even air. As a result, every object has a mass, which determines whether it is light or heavy.The amount of matter in a thing is measured by its mass.To learn more about mass refer to:
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What is the relationship between the mass of an object and the amount of thermal energy an object has?
The greater the mass of an object, the more particles there are in the sample and the more thermal energy it possesses at the same temperature. Assume you have some boiling hot water at 100 degrees Celsius to demonstrate this concept.
What is thermal energy and what are some examples?Thermal energy is shown by boiling water on a stove. Thermal energy is created when the atoms and molecules of a material vibrate faster as the temperature rises.
What is an example of a mass?Mass is best defined as the quantity of matter contained in any item or body. Everything in our environment has mass. For example, a table, a chair, your bed, a football, a glass, and even air has mass. That being said, all objects are light or heavy because of their mass.
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You throw a ball vertically upward so that it leaves the ground with velocity 5. 68 m/s.
(a) What is its velocity when it reaches its maximum altitude? magnitude 0 Correct: Your answer is correct. M/s direction Incorrect: Your answer is incorrect.
(b) What is its acceleration at this point? magnitude -9. 8 Incorrect: Your answer is incorrect. The response you submitted has the wrong sign. M/s2 direction Incorrect: Your answer is incorrect.
(c) What is the velocity with which it returns to ground level? magnitude -5. 68 Incorrect: Your answer is incorrect. The response you submitted has the wrong sign. M/s direction Correct: Your answer is correct.
(d) What is its acceleration at this point? magnitude 9. 8 Correct: Your answer is correct. M/s2 direction Correct: Your answer is correct
The length of time needed to descend back to the earth's surface. Gravitational acceleration is equal to -9.8 m/s2. 2 s^2 s2
Explanation for the above answer:When anything is sent vertically upward, it slows down due to gravity. Up until it reaches a maximum height, where the velocity is zero, its speed is decreasing. After that, gravity accelerates it uniformly downward.
The three equations are as follows: v = u + at, v2 = u + 2as, and s = ut + 12at2.
What is the vertical velocity formula?With this knowledge, the vertical velocity formula, vf=vi+gt v f = v I + g t, can be used to calculate the object's terminal velocity. This equation is used by physicists to predict how any object will move on a vertical plane.
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1 pts What is the work required to raise a 25.0 kg object from the surface of the Earth to a height of 3.33 m
The work required to raise a 25.0 kg object from the surface of the earth to a height of 3.33 m
Formula: F = 25.0, D = 3.33, and W =?
W = F x D
Putting values together equals 25.0 x 3.33 W = 83.25 j.
Work = force times distance, or W = Fd.
F = W/d for force
Distance: W/F = d
W = work, F = force, and D = distance.
The integral of such a force applied over a displacement distance is referred to as "work." When one engages in work, they are doing something that requires them to use their strength or force.
When energy is transferred to an item, it is considered to have undergone work in science.
The integral of such a force applied over a displacement distance is referred to as work. When one engages in work, they are doing something that requires them to use their strength or force.
When energy is transferred to an item, it is considered to have undergone work in science.
The physics formula for work
The physics equation or formula is:
W = Fd
Work (force times distance)
For force, F = W/d.
Distance: W/F = d
The scalar dot product of force and displacement also yields work.
FDCos = W
Work-related SI unit :
Joule is the SI unit of work (J). The work performed by a force of one newton operating over a distance of one meter is defined as one joule in this context. kgm2s-2 is the SI base unit of work.
Work can be defined as the quantity of energy that a force transfers. Calculate work Another name for physics is the joule calculator. Work is represented by the letter "W."
Work is defined as a motion that is caused by a resisting force and is quantified by the force's product into the motion component that is resolved in the force's direction. The size of it is ML2T-2.
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Select the correct answer from each drop-down menu. steel is an alloy of . one of the main reasons steel is used more widely than iron is because it’s than iron.
Steel is an alloy of iron and carbon. One of the main reasons steel is used more widely than iron is that it’s stronger than iron.
Steel, unlike other forms of iron, is strengthened by the addition of carbon, making it more resistant to fracture. Additional components are possible or even expected. To prevent corrosion and oxidation, stainless steels typically contain an extra 11% chromium. Steel's low price and high tensile strength make it a popular material for many different types of construction, as well as for transportation, manufacturing, and defense. Cast iron is the primary component of steel. It can crystallize in either a body-centered cubic or a face-centered cubic form, depending on the temperature. Steel and cast iron are characterized by a wide variety of properties due to the interaction of iron's various allotropes with the alloying elements, most notably carbon.
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where does sound travel faster(the desert or the forest)?
Answer:
forest
Explanation:
cause of the echo
Answer:
forest
Explanation:
very spacious enough to make echo
At t = 0, a wheel rotating about a fixed axis at a constant angular acceleration of -0.40 rad/s2 has an angular velocity of 1.5 rad/s and an angular position of 2.3 rad. what is the angular position of the wheel at t = 2.0 s?
At t = 0, the wheel has an angular position of 2.3 rad and an angular velocity of 1.5 rad/s.
Since the wheel is rotating about a fixed axis at a constant angular acceleration of -0.40 rad/s2, we can use the equation for angular position to calculate the wheel's angular position at t = 2.0 s.
Angular position = initial angular position + (initial angular velocity × time) + (1/2 ×angular acceleration ×time²)
Angular position at t = 2.0 s = 2.3 rad + (1.5 rad/s × 2.0 s) + (1/2 ×-0.40 rad/s2 × (2.0 s)²)
Angular position at t = 2.0 s = 2.3 rad + 3.0 rad + -1.6 rad
Angular position at t = 2.0 s = 3.7 rad
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Burning coal yields about 30 X 106 J of energy per kilogram of coal burned. Assuming that the coal power plant is 30% efficient, how much coal has to be burned to light that light bulb for one day
1 kilogramme of coal can provide 8 kWh of heat, hence power output here =30x8x10e6/1day =30x8x10e6x24 hours=2.7e15 joules
what is coal used for ?
In the United States, coal is largely utilised as a fuel to create electricity. Bituminous coal, subbituminous coal, or lignite are burnt in coal-fired power plants. The heat generated by coal combustion is utilised to turn water into high-pressure steam, which powers a turbine and generates electricity. According to the US Energy Information Administration, coal-fired power stations provided around 23% of all energy in the United States in 2019.
Steel may also be made from certain kinds of bituminous coal. Coal used to make steel must have a high carbon content while being low in moisture, ash, sulphur, and phosphorus. Metallurgical coal is coal that fits certain requirements.
1 kilogramme of coal can provide 8 kWh of heat, hence power output here =30x8x10e6/1day =30x8x10e6x24 hours=2.7e15 joules
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