Dark matter was first detected because the excess for the amount of gravity that could be present due to the luminous mass.
Since, by measuring the rotation of the galaxies and their gravitational attraction, the scientists determined that there appeared to be an excess of gravity, which could not be explained by the amount of luminous mass present. This led to the conclusion that dark matter must exist to explain this excess gravity.
The role of dark matter in the formation of galaxiesDark matter plays a fundamental role in the formation and evolution of galaxies. This invisible matter is composed of subatomic particles that interact with gravity, but does not emit light, so it cannot be detected directly. Despite this invisibility, advances in technology have allowed scientists to determine the amount of dark matter present in the Universe and its contribution to the evolution of galaxies.
Studies of galaxies suggest that dark matter plays an important role in their formation, this means that dark matter is responsible for the formation of galactic structures, such as disks and the central bar.
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A 0.321 kg, 0.27 m radius thin shelled ball rolls (starting at rest) 3.82 m from the top down a 35 degree 10.0 m long incline without slipping. After the 3.82 m, the incline becomes frictionless for the rest of the board. After 0.8 m of the frictionless unencumbered movement, the ball reaches a frictionless, massless spring with a spring constant of 20 N/m.
a) How fast is the center of mass of the ball going after 3.82 m? (linear speed)
b) How fast is the ball rolling after the 3.82 m? (angular speed)
c) How much does the spring compress?
d) What is the ball's maximum linear speed?
e) What is the balls angular speed with the spring is fully compressed?
I need this answered by tomorrow night, so please don't rush this one too bad... I would like step-by-step solutions not just answers.
Answer:
Explanation:
Hope you can give me "Brainliest" answer is will help a lot! Thank you
To solve this problem, we can use the following equations:
Linear speed: v = d/t
Angular speed: w = v/r
Spring compression: x = (1/2)kx^2
Conservation of energy: KE = PE
a) To find the linear speed of the center of mass after 3.82 m, we can use the equation v = d/t. We know that d = 3.82 m and t = 1 s (since the ball is starting from rest). Plugging these values into the equation gives us:
v = 3.82 m / 1 s = 3.82 m/s
This is the linear speed of the center of mass after 3.82 m.
b) To find the angular speed after 3.82 m, we can use the equation w = v/r. We know that v is 3.82 m/s (the linear speed we just found) and r is 0.27 m (the radius of the ball). Plugging these values into the equation gives us:
w = 3.82 m/s / 0.27 m = 14.15 rad/s
This is the angular speed of the ball after 3.82 m.
c) To find the spring compression, we can use the equation x = (1/2)kx^2. We know that k is 20 N/m (the spring constant) and x is the spring compression (which we are trying to find). Plugging these values into the equation gives us:
x = (1/2)(20 N/m)(x^2)
To solve for x, we can rearrange the equation to get:
x^2 = (2/k)x
Substituting in the value for k gives us:
x^2 = (2/20 N/m)x
Solving for x gives us:
x = sqrt(2/20 N/m) = 0.2 m
This is the spring compression.
d) To find the maximum linear speed, we can use the conservation of energy equation KE = PE. We know that KE is the kinetic energy of the ball (which is equal to (1/2)mv^2) and PE is the potential energy of the ball (which is equal to mgh, where m is the mass of the ball, g is the acceleration due to gravity, and h is the height of the incline). We also know that the ball starts at the top of the incline with a height of h = 10 m and that it rolls down the incline a distance of d = 3.82 m. We can use these values to find the final height of the ball, h2, using the equation h2 = h - d = 10 m - 3.82 m = 6.18 m.
Substituting these values into the conservation of energy equation gives us:
(1/2)mv^2 = mgh2
Solving for v gives us:
v = sqrt(2gh2/m) = sqrt(2(9.8 m/s^2)(6.18 m)/0.321 kg) = 6.58 m/s
This is the maximum linear speed of the ball.
e) To find the angular speed with the spring fully compressed, we can use the equation w = v/r. We know that v is the maximum linear speed we just found (6.58 m/s) and r is the radius of the
The Sun radiates energy at a rate of about 4×1026W. Earth is about 150×106km from the Sun.
Estimate the energy coming to Earth from the Sun each second. The radius of Earth is about 6400 km .
The average intensity received on the Earth's surface is [tex]12.6*10^{10} W/m^{2}[/tex]
[tex]Intensity = Rate of energy radiated/4\pi R^{2}[/tex]
where R is the distance of the earth from the sun.
[tex]I=4*10^{26}/4\pi *[150*106*10^{3}]^{2}[/tex]
[tex]I=0.12597*10^{12}[/tex]
[tex]I=12.6*10^{10} W/m^{2}[/tex]
What is the meaning of the intensity of sunlight?
Sun intensity refers to the amount of incoming solar energy, or radiation, that reaches the Earth's surface. The angle at which the rays from the sun hit the Earth determines this intensity.
What is the average intensity received on the Earth's surface?
The average intensity received on the Earth's surface is given by:
[tex]I=rate of energy radiated/4\pi R^{2}[/tex]
Thus, the average intensity received on the Earth's surface is [tex]12.6*10^{10} W/m^{2}[/tex]
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a 16 kg box sitting at the top of an icy hill begins to slide down the essentially frictionless surface. at the bottom of the hill it collides with a spring loaded guardrail with a spring constant of 384 N/m. if the hill is 7.1 m high, how much did the box compress the spring?
The compression of the spring of spring constant 384 N/m is 2.41 m.
What is compression spring?Compression springs work by resisting and pushing back against any downward or inward force that tries to squash and hold them in a compressed state.
To calculate the compression of the spring, we use the formula below.
Formula:
e = √(2mgh/k)........... Equation 1Where:
e = Compression of the springm = Mass of the boxh = Heightg = Acceleration due to gravityk = Spring constantFrom the question,
Given:
m = 16 kgh = 7.1 mg = 9.8 m/s²k = 384 N/mSubstitute these values into equation 1
e = √(2×16×7.1×9.8/384)e = 2.41 mHence, the compression of the spring is 2.41 m.
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The speed of light depends on the medium. Refractive index of the water is 1.33 and for glycerin is 1.473.
The medium determines the speed of light in which light is travelling.
The refractive index is the ratio of the speed of light in the vacuum to the speed of light in that particular medium. The speed of light in a vacuum is 3 x 10⁸ m/s
n = c/v
c = speed of light in the vacuum
v = speed of light in the medium
n = refractive index of the medium
The Refractive index of the water is 1.33 and for glycerin is 1.473. It means the speed of light is more in water than in glycerin. This occurs because of more density in glycerin as compared to water. The material with greater density hampers the speed of light.
Hence, more the refractive index of water slower light travel through it.
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Questions
Answer questions in complete sentences.
1. Compare the accelerations for the three trials. Explain how Newton's second law was demonstrated in the simulation?
2. Describe how Newton's first and third laws would apply to this situation if this simulation was done in the real world.
3. Compare the masses that you calculated for the three trials. If the actual mass of the cart did not change (same cart for all trials), what measurement do you believe contributed the largest amount of error to that calculation? Explain your answer.
Data Collection—Table 1:
Trial Force used (N) Time (s) Distance (m) (fixed) Acceleration (m/s2) Mass (kg)
1 200 4.77 5.0 0.21 952.38
2 300 3.82 5.0 0.34 882.35
3 50 9.39 5.0 0.05 1000
Furthermore, according to Newton's Second Law, the force required to accelerate an object increases with its mass.
What evidence is there for Newton's second law?When a ball is struck, it accelerates to a certain degree. The force exerted on the ball immediately correlates to the acceleration with which it moves. Consequently, Newton's second rule of motion is demonstrated in real life by the fact that the ball moves quicker the harder you strike it.
What is the connection between acceleration and Newton's second law?A force exerted on an object causes it to accelerate in accordance with Newton's Second Law of Motion, commonly referred to as the Law of Force and Acceleration or the Law of Force and Mass.
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The odometer of a car indicates the total distance travelled by the vehicle. A driver looks at his odometer at two instances while he is driving (as shown below). Given that the diameter of the wheels of the vehicle is 75 cm, what is the average number of revolutions completed by each wheel in 1 minute?
A. 71
B. 283
C. 1200
D. 12700
The average number of revolutions completed by each wheel in 1 minute is 283 rounds.
What is distance?
Distance is the amount of space between two points or objects. It is a measure of length and can be measured in a variety of units such as kilometers, miles, or even light-years. Distance is an important concept in mathematics, used to calculate the length of a line segment, the circumference of a circle, the area of a triangle, and the volume of a sphere. It is also used in everyday life, such as calculating the distance between two cities, or the distance a car has traveled. Distance can also be used to compare the size of things, such as the relative distance between planets.
It is symbolized as km /sec.
as per the given question-distance= 20650.5-20950.5=60km
Time = 14:04-12:34=1 hour 30 minutes
1 hour 30 minutes = 90 minutes
wheel radius = 75÷2 = 37.5 cm
wheel circumterence =235.62cm
we know,
Average speed= distance/circumentace /time
60km/235.62cm/90 = 283 rounds.
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Which statement is true about the motion of a planet in its orbit around the Sun?
A: The orbital speed increases as the planet approaches apogee.
B: The orbital speed of the planet remains constant as it orbits the Sun.
C: The planent's orbital speed changes as it moves closer and farther from the Sun.
D: Perigee is when the orbital speed is at its least.
The statement that is true about the motion of a planet in its orbit around the Sun is the planet's orbital speed changes as it moves closer and farther from the Sun. The correct option is C.
What is the motion of planets?The motion of a planet is explained by Kepler's law of motion. Kepler's laws of planetary motion are physics rules that govern the motions of the planets in the solar system. They were developed by the German astronomer Johannes Kepler.
According to Kepler's first law of planetary motion, the path that the planets take around the sun is elliptical, with the sun's center at one focus. The distance between the Sun and the planets changes as they orbit the Sun.
Therefore, the correct option is C: The planet's orbital speed changes as it moves closer and farther from the Sun.
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On a hot summer day, you decide to make some iced tea. First, you brew 1.50 L of hot tea and leave it to steep until it has reached a temperature of tea = 75.0 ∘C. You then add 0.975 kg of ice taken from the freezer at a temperature of ice = 0 ∘C. By the time the mix reaches equilibrium, all of the ice has melted. What is the final temperature T of the mixture? Find the equilibrium final temperature T of the system.
The final temperature of the mixture is 17.9 °C.
How find the final temperature?The final temperature of the mixture can be found using the formula for heat exchange between two bodies at different temperatures: Q = mcΔT, where Q is the heat exchanged, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature.
For the tea, Q = mcΔT = (4.18 J/g·°C)(1.50 L)(1000 g/L)(75.0 - T)
For the ice, Q = mcΔT = (2.09 J/g·°C)(0.975 kg)(0 - T)
Since the total heat in the system is conserved, the heat gained by the tea is equal to the heat lost by the ice. So, we can set the two equations equal to each other and solve for T.
(4.18 J/g·°C)(1.50 L)(1000 g/L)(75.0 - T) = (2.09 J/g·°C)(0.975 kg)(0 - T)
T = (75.0 - (2.09 J/g·°C)(0.975 kg)/(4.18 J/g·°C)(1.50 L)(1000 g/L)) = 17.9 °C
So, the final temperature of the mixture is 17.9 °C.
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Need to fill in the blank
Neglecting drag, the cannonball's initial height, and its horizontal motion, the maximum height rise is 110.45 metres, the time it takes for the ball to rise is 4.7 seconds, and the overall flight duration is 9.4 seconds.
Equation:
A pupil propels a cannonball 47.0 metres per second vertically upward.
assuming that the acceleration brought on by gravity is 10 m/s2.
Using the equation U2 = 2gH, the cannonball's highest point will be determined.
where H is the height the cannonball reaches.
When all the figures are put together, 47*47 = 2*10*H
H = 110.45 metres.
The cannonball's ascent time would be given by t=(2H/g).
When all the values are put together, t = (2*110.45/10)t = 4.7 seconds.
The cannonball's total flight time, T, is equal to the sum of its rise and descent times.
The ratio of ascent to descent is time.
Time of ascension = 4.7 Seconds since there is no other acceleration present and it is motion under gravity.
T = 2×(time of ascent) (time of ascent)
9.4 seconds are equal to T = 2*4.7.
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14C is produced in the upper atmosphere by cosmic rays. Living organisms uptake 14C. Assume we isolate the same quantity of 14C from a 1000 year old fossil and from a recently harvested tomato. We monitor the decay of these quantities.
A. The carbon islated from the tomato plant will have more decays per second that the carbon isolated from the fossil
B. The two samples will have approximately the same number of decays per second.
C. The carbon isolated from the fossil will have more decays per second that the carbon isolated from the tomato plant.
D. It is impossible to compare the decay rates, since nuclear decay is a random process.
The average decay rate for the two samples will be about the same.
The correct option is B.
What happens if cosmic rays hit the Earth?Cosmic rays that reach Earth have the potential to interact with atom nuclei in the atmosphere, producing billions of fission fragments in the process. Cosmic rays were the sole technique to examine subatomic particles before people created the first photon accelerators in the 1950s.
What examples of cosmic rays?HZE ions are the name for these high-mass, high-charged particles. Numerous sources produce primary cosmic rays. They may originate from sunspots or solar explosions, for instance. The term "solar energetic particles" is frequently used to describe the particles released by the sun.
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Conservation of Momentum - A 5 kg mass has a speed of 3 m/s to the right when it hits and sticks to a 4 kg mass. If the final combined speed is 2 m/s to the right, what was the initial velocity of the second object. Pick the closest answer. A) 1.2 to the right B) 1.2 to the left C) 0.75 to the right D) 0.75 to the left
The system is working based on the Conservation of Momentum: A 5kg mass has a speed of 3m/s to the right when it hits and sticks to a 4 kg mass that moves with speed of 0.75m/s to the right (C). Both mass then move together with 2m/s to the right.
Conservation of momentum states that the total momentum of a system remains constant.
P = P'
Momentum is the product of a particle's mass and velocity. Momentum could be formulized as:
P = m.v
From the case, we know that:
m1 = 5kg
m2 = 4kg
v1 = 3m/s to the right
v1' = v2' = v' = 2m/s to the right
v2 = ?
Based on the conservation of momentum concept, we know that:
P = P'
where:
P = m.v
Hence:
P = P'
m1.v1 + m2.v2 = (m1 + m2)v'
5 (3) + 4 (v2) = (5+4) 2
15 + 4v2 = 18
4v2 = 3
v2 = 0.75 m/s --> because v2 positive, hence m2 is moving to the right
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How did Edwin Hubble classify spiral galaxies?
O according to the width of their spiral arms
O according to the length of their lives
O according to the tightness of their spiral arms compared to the size
of their nuclear bulges
O according to the density of their spiral arms and nuclear bulges
Answer:
The correct answer is C.
Explanation:
Edwin Hubble classified spiral galaxies according to the tightness of their spiral arms compared to the size of their nuclear bulges. This classification scheme, known as the Hubble sequence, is based on the observation that spiral galaxies can have different degrees of spiral arm tightness and different sizes of nuclear bulges. By comparing these two features, Hubble was able to divide spiral galaxies into three main categories: barred spirals, normal spirals, and flocculent spirals. The classification of a spiral galaxy into one of these categories depends on the relative size of its nuclear bulge and the tightness of its spiral arms.
Answer:
How did Edwin Hubble classify spiral galaxies?
according to the tightness of their spiral arms compared to the size of their nuclear bulges
Explanation:
Took the K12 test.
Which planet has the strongest gravity at its equator
Answer:
Jupiter
Explanation:
It has the highest gravitational pull
Review what you learned in the unit about attribution theory. Explain in your own words what it is. Describe how attributions affect the way we explain behavior. In what way can attribution theory be harmful? In what way can it be helpful?
Attribution theory describes how an individual says or thinks that something is a as a result of a person's deed or an action of an external factor.
The cause of behavior is attributed to some internal characteristic of a person rather than external forces.
It can be harmful because attributing a person's character to a mistake can lead to underestimation of an individual.
Attribution helps an individual to understand the reason behind another person's behavior and thinking.
What is Attribution theory?Attribution theory is related to how ordinary people explain the causes of behavior and events that follow it. This helps them understand how they receive, interpret action, and how they give form an opinion of them.
When an person displays certain behaviors, they are usually attributed to certain internal characteristics. This theory can be harmful to explaining behavior because mistakes are attributed to character instead of external factors leading to underestimating people. On the other hand, it is beneficial to understanding people.
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If Impulse is the change in momentum using forces, how would you have to change a large amount of force with a small force?
a .You will have to apply the force over a longer period of time
b. You will have to apply the force at a different direction
c. You will have to have more than one force present
d. You will have to decrease the total impulse acting on the object
To change a large amount of force with a small force, you will have to apply the force over a longer period of time. So, option (a) is correct.
What is impulse?In physics, the term "impulse" is used to characterize or measure the impact of force operating gradually to alter an object's motion. It is often stated in Newton-seconds or kilograms per second and is denoted by the symbol J.
Product of the average force applied to an object throughout time and the time period during which it is applied is impulse. The change in momentum is the same as impulse.
You will have to apply the force over a longer period of time to create large amount of impulse with a small force.
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a man is trying to move his washing machine into the back of a removal van. the washing machine has a weight of 650N and the floor of the removal van is 0.80 metres above the ground. calculate the efficiency of the ramp
Answer:650 * 0.8
Explanation:520
What is the relationship between MASS and DENSITY?
As well as VOLUME and DENSITY?
A solar panel receives energy from the Sun at a rate of 5.0 kW.
Thermal energy is transferred from the solar panel to water with an efficiency of 20%.
Cold water of mass 15 kg enters the solar panel every hour.
The specific heat capacity of water is 4200 J/(kg °C).
Calculate the temperature increase of the water.
The temperature increase of the water is 57.1⁰C.
What is the change in temperature of the water?
The temperature increase of the water is determined by calculating the change in temperature of the water.
Q = mcΔθ
where;
Q is the quantity of heat transferred to the waterm is the mass of the waterΔθ is the change in temperature1 hour = 3600 seconds
The quantity of heat water transferred to the water = e x P x t
where;
e is the efficiency of the solar panelP is powert is the time duration( 0.2 x 5,000 x 3600 ) = 15 x 4200 x Δθ
3,600,000 = 63,000Δθ
Δθ = 3,600,000 / 63,000
Δθ = 57.1 ⁰C
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c) A physicist while calculating the charge over on an object found that 6× 10-¹⁹ ℃ cannot be the magnitude of the charge on an object. Justify.
An electron has a charge that is equal to the size of the elementary charge, e, with a negative sign. The value of the elementary charge is 1.602 x 10-19 C.
Positive and negative electric charges are two distinct types that are known to exist. Electrons have a negative charge, whereas protons have a positive charge. The item has a positive net charge if there are more protons than electrons. The net charge of an object is considered to be negative if there are more electrons than protons. If there are an equal number of protons and electrons, the object is considered to be electrically neutral.For more information on electric charge kindly visit to
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The speed of sound (velocity) is 343 m/s and a burglar alarm on a car has a frequency of 1200hz. What is the wavelength of the burglar alarm on the car? Formula is Wavelength=Velocity/Frequency
PLEASE HELP!!
The speed of sound (velocity) is 343 m/s and a burglar alarm on a car has a frequency of 1200hz. 0.286 m/sec is the wavelength of the burglar alarm on the car.
What is frequency?Frequency is a unit of measurement for how frequently a recurrent event, like a wave, takes place over a specified period of time. A cycle is one repetition of the repeating pattern. Frequency only exists in moving waves that change their places throughout time. One method to describe how quickly a wave moves is by its frequency.
Therefore, if a wave passes through in half a second, the frequency is 2 per second. The frequency is 100 times per hour if it takes 1/100 of an hour.
Given that,
speed of sound (velocity) is 343 m/s
frequency of 1200 Hz.
Now as we know,
v = n × λ
or, λ = v/n
or, λ = (343 m/sec) / 1200 Hz.
or, λ = 0.286 m/sec
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Part A Which of the following changes would make the water balloon more likely to pop? (Ignore effects of convection within the fluid.) Select all that apply. View Available Hint(s) Use a liquid that has a higher heat capacity than water Use a thicker balloon. Use a liquid that has a lower heat capacity than water. D Use a thinner balloon. Part A Which of the following changes would make the water balloon more likely to pop? (Ignore effects of convection within the fluid.) Select all that apply. View Available Hint(s) Use a liquid that has a higher heat capacity than water Use a thicker balloon. Use a liquid that has a lower heat capacity than water. D Use a thinner balloon.
The change that would make the water balloon more likely to pop is:
to use a liquid that has a lower heat capacity than waterto use a thicker balloon.The correct options are B and C
What is heat capacity?Heat capacity or also known as thermal capacity is a physical property of matter, defined as the amount of heat to be supplied to an object to produce a unit change in its temperature.
So, Using a liquid that has a lower heat capacity than water and using a thicker balloon will make the water balloon more likely to pop.
We know now that heat capacity or specific heat is the amount of heat per unit mass that is required to raise the temperature by 1°C and this is helpful in determining the processing temperatures and amount of heat necessary for processing and can be helpful in differentiating between two polymeric composites.
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When matter undergoes a change in form but the chemical make up is not changed it is a ?
Answer: Law of conservation of mass
Explanation:
A copper cable is 1.2 km long and has a cross-sectional area of 5 mm^2. Find its resistance at 80°C if at 20°C the resistivity of copper is 0.02*10^-6ohm m and its temperature coefficient of resistance is 0.004/°C
Explanation:
Equation for resistity
[tex]p(t)= p(0) \times (1 + a \times (change \: in \: temp))[/tex]
[tex] = 0.02 \times {10}^{ - 6} \times (1 + 0.004 \times 60)[/tex]
[tex] = 2.48 \times {10}^{ - 8} ohm \: m[/tex]
[tex]r = (p \times l) \div a[/tex]
[tex] = (2.48 \times {10}^{ - 8} \times 1200) \div \: 5 \times {10}^{ - 6} [/tex]
[tex] = 5.952 \: ohms[/tex]
A doubly ionized lithium atom is in the ground state. It absorbs energy and makes transition to the n = 5 excited state. The ion returns to the ground state by emitting several photons. What is the wavelength of the highest energy photon?
The wavelength of highest photon energy is 0.544J.
Use the equation to calculate the electron's energy in the nth orbit. Calculate the energies of the first and third Bohr orbits to determine the amount of energy needed to excite the electron. The wavelength of a photon can be calculated using the photon energy formula. Check how many different routes an excited electron can take to reach its ground state, the first Bohr orbit.[tex]E=-\frac{13.6}{y^2}[/tex]E=-13.6/5²=0.544 JTo study about ground state -
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A box with a mass of 1.5 kg is pulled across the floor with a constant velocity by a force of 37 N. What is the coefficient of friction? Show
work for full credit.
A box with a mass of 1.5 kg is pulled across the floor with a constant velocity by a force of 37 N, the coefficient of friction is 2.52
What is friction?The force that resists the motion of one solid object over another is known as friction. The four basic forms of friction are fluid friction, rolling friction, sliding friction, and static friction.
Friction is a sort of contact force. It exists between surfaces that are in touch with one another.
Given that,
Mass (m) = 1.5 kg
force (F) = 37 N
As we know,
co-efficient of friction (μ) = F/mg
μ = 37 N / (1.5 kg × 9.8 m/sec)
μ = 2.52
Thus, co-efficient of friction = 2.52
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Answer:
ok the final answer is μ = 2.52
Explanation:
I did the question on the flvs the first explanation is correct
A skateboarder with a mass of 120 kilograms (including the skateboard) is traveling at a speed of 5.00 meters per second upon reaching the bottom of a ramp. Between the top of the ramp and the bottom, the skateboarder lost 150 joules of thermal energy due to friction. What was the potential energy of the skateboarder at the top of the ramp?
6,150 J.
5,850 J.
1,650 J.
1,350 J.
The potential energy of the skateboarder at the top of the ramp was 1650 joule.
What is laws of conservation of energy?The law of conservation of energy asserts, in essence, that: The total energy of the system is preserved in a closed system, or a system that is separated from its surroundings.
Given that: A skateboarder with a mass of 120 kilograms (including the skateboard) is traveling at a speed of 5.00 meters per second upon reaching the bottom of a ramp.
So, his kinetic energy = 1/2×mass×speed² = 1/2 × 120 × 5² = 1500 Joule.
Loss of energy due to friction = 150 joule.
So, the potential energy of the skateboarder at the top of the ramp be = 1500 Joule + 150 joule = 1650 joule.
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Choose the one which is False.
1. If the speed changes, the velocity also changes.
2. If the speed changes, there is acceleration.
3. If the speed does not change, but the direction changes, there will be acceleration.
4. Motion with constant velocity is accelerated motion.
5.
Motion along a straight line is Linear motion.
Answer:
4
Explanation:
1 is true. Speed is the magnitude of velocity so if the magnitude of velocity(speed) changes, then velocity changes itself.
2 is true.
[tex]a _{avg} = \frac{v _{f} - v _{i} }{t} [/tex]
Since speed changes, the inital and final speeds are different, therefore we will have some nonzero acceleration because the numerator does not equal zero.
3 is correct, acceleration is a vector so it has direction, meaning if the direction of speed changes then we will have acceleration.
4. is false, a constant velocity has a acceleration of 0.
5 is correct, motion along a straight line is linear.
The half-life of chromium-51 is 28 days. If the sample contained 510 grams, how much chromium (in grams) would remain after 1 year?
Answer: 0.061gm
Explanation:
A capacitor is connected to an AC source. If the maximum current in the circuit is 0.400 A and the voltage from the AC source is given by Δv = (82.8 V) sin[(86π)s−1t], determine the following.
a) the rms voltage (in V) of the source
b) the frequency (in Hz) of the source
c)the capacitance (in µF) of the capacitor
The RMS Voltage , Frequency and capacitance of capacitor is 82.8V,6.28Hz and 2.34F
Because the RMS value provides the amount of AC power drawn by a resistor that is comparable to the power drawn by a DC source, the RMS voltage is also referred to as the equivalent DC voltage. Consider a 10V DC source and a 5 load as an example. When using a DC source, the voltage value remains constant throughout all time.A potential difference is created across the capacitor by the buildup of charges in the conductors. The capacitor's capacity to hold a charge is determined by how much charge has accumulated. Capacitance is the name for this ability to hold a charge. The voltage created across the capacitor is directly proportional to the charge that has built up in the capacitor.Q ∝V .
Q = C/V.
C = Q/V.
RMS voltage =82.8VFrequency=2πw=2 x 3.14 x 1 =6.28Hzcapacitance=86/82.8=2.34 FTo find more about RMS Voltage-
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A Composite wall is shown with surface temperatures T0 and TL. Layer 1 has a conductivity k1, Thickness L1 and layer 2 has conductivity k2, thickness L2. The cross sectional area of both layers is A.
L1/k1A + L2/k2A is the total thermal resistance between the surfaces at temperatures T0 and TL.
What does heat resistance actually mean?A measurement of the temperature differential at which a material or item resists the transfer of heat is known as thermal resistance. Thermal resistance is the inverse of thermal conductivity. Since the bulk of electrical components generate heat and need cooling, thermal resistance of materials is of special interest to electronic engineers. Electronic components might malfunction or fail due to overheating, hence special care must regularly be taken while designing those components.
What relationship does thermal conductance have with resistance?Engineering regularly uses another important concept. Since there is a resemblance between the dispersion of heat and electrical charge, engineers typically use the thermal resistance (i.e., thermal resistance vs heat conduction) to compute heat transport through materials. Thermal resistance is the reverse of thermal conductivity.
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The complete question is,
A composite wall is shown with surface temperatures T0 and TL. Layer L1 has conductivity K1, thickness L1 and layer 2 has conductivity k2, thickness L2. The cross-sectional area of both layers is A. The total thermal resistance between the surfaces at temperatures T0 and TL is.