A ball is dropped from a height of 32 feet. it bounces and rebounds 80% of the height from which it was falling

In any electrical circuit where current is flowing, Electrons are the particles that are doing the flowing.  (d)

Statements  A,  B,  and  C  are true.

Statement D  is false.

The false statement is that iron filings will be clustered more densely where the magnetic field is weakest. In reality, the filings align more closely where the field is strongest. So the correct option is D.

The false statement about iron filings placed upon glass resting on top of a bar magnet is that the filings will be clustered more densely where the field is weakest. To address the given statements:

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The question is about calculating the efficiency of an automobile engine given its fuel consumption rate, power output, fuel heating value, and fuel density. The efficiency of the engine was determined to be roughly 25.5 percent through a step-by-step calculation involving several unit conversions.

The efficiency of an engine can be calculated using the formula: Eff = W/Qh, where W signifies the work output and Qh indicates the heat input to the engine. To calculate the efficiency of the automobile engine given in the problem, we first need to convert the power from kw to kj/s, fuel rate from l/h to kg/s and then find the heat input using the heating value of the fuel.

Thus, the efficiency of this engine is approximately 25.5 percent.

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The efficiency of the engine, calculated as the output power divided by the input power, is 25.6%.

To calculate the efficiency of the engine, we first have to determine the energy input and output.

The output is given directly as 55 kW.

For the input, we use the heat content and flow rate of the fuel.

The fuel consumption is 22 l/h, with a density of 0.8 g/cm³, which equals 17600 g/h.

The energy input, therefore, is 44,000 kJ/kg x 17.6 kg/h = 774400 kJ/h = 215 kWh.

Efficiency is defined as the output divided by the input, so in this case, the engine efficiency is

55 kW / 215 kW = 0.256, or 25.6% when expressed as a percentage.

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a. The resistance will increase

b. The current will decrease

c. The voltage through each bulb will

Explanation:

a. For a series of resistors, the equivalent resistance is given by

[tex]R=R_1+R_2+...+R_n[/tex]

so, we see that adding more resistors in series, will increase the total resistance.

b. In a series circuit, the current through each bulb is the same for each bulb, and it is equal to the current flowing in the circuit, which is given by Ohm's law

[tex]I=\frac{V}{R}[/tex]

where V is the voltage supplied by the battery and R the total resistance of the circuit. Since the voltage provided by the battery, V, does not change, while the total resistance R increases, the current I will increase.

c. The voltage through each bulb is given by

[tex]V=R_i I[/tex]

where R_i is the resistance of the individual resistor and I is the current. Since the value of R_i does not change, while I (the current) has decreased, the voltage available to each bulb, V, will decrease.

Mechanical energy remains constant (conserved) if only conservative forces act on the particles.  

In this sense, the following forces are conservative:  

-Gravitational  

-Elastic

-Electrostatics  

While the Friction Force and the Magnetic Force are not conservative.

According to this, mechanical energy is conserved in the presence of electrostatic and gravitational forces.

Answer:

emits a photon

Explanation:

When an electron in a quantum system drops from a higher energy level to a lower one, the system emits a photon. According to the law of conservation of energy, the energy of the emitted photon is equal to the difference in energy between the two energy levels:

[tex]\Delta E= E_1 -E_2[/tex]

The opposite transition can also occur: the system can absorb a photon such that the electron jumps from the lower energy level to the higher level. As before, the energy of the emitted photon is equal to the difference in energy between the two energy levels:

[tex]\Delta E= E_2 -E_1[/tex]

Answer:

[tex]R' = \frac{1}{\sqrt{3}}R[/tex]

Explanation:

The acceleration due to gravity on the surface of the Earth is given by:

[tex]g=\frac{GM}{R^2}[/tex]

where

G is the gravitational constant

M is the mass of the Earth

R is the radius of the Earth

Here we want to find the new Earth radius R' for which the gravitational acceleration at the surface, g', would be 3 times the current value of g:

[tex]g' = 3g[/tex]

So we would have

[tex]\frac{GM}{R'^2}=3(\frac{GM}{R^2})[/tex]

Solving the equation for R', we find

[tex]R'^2 = \frac{1}{3}R^2\\R' = \frac{1}{\sqrt{3}}R[/tex]

The fraction of the Earth's current radius at which the free-fall acceleration at the surface would be three times its present value is √3/3.

To find the fraction of its current radius at which the free-fall acceleration at the surface of the Earth would be three times its present value, we need to understand the relationship between the radius and gravitational force. The gravitational force is inversely proportional to the square of the radius. Therefore, if we shrink the Earth's radius to a fraction x, the gravitational force would increase by a factor of (1/x^2).

Let's set up an equation using this relationship:

3 * present acceleration = (1/x^2) * present acceleration

Simplifying the equation, we get:

x^2 = 1/3

Taking the square root of both sides, we find:

x = √(1/3) = 1/√3 = 1/√3 * √3/√3 = √3/3

Therefore, the fraction of the Earth's current radius at which the free-fall acceleration at the surface would be three times its present value is √3/3.

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Answer:

10 kg m/s

Explanation:

According to the law of conservation of momentum, the total momentum before the collision must be equal to the total momentum after the collision. So, we can simply calculate the total momentum before the collision.

The two balls are moving in perpendicular directions - one eastward and one northward. If we take eastward as positive x-direction and northward as positive y-direction, this means that we can find the magnitude of the total momentum by simply using Pythagorean theorem.

The magnitude of the momentum of the ball travelling eastward is:

[tex]p_1 = m_1 v_1 = (2.0 kg)(3.0 m/s)=6.0 kg m/s[/tex]

The magnitude of the momentum of the ball travelling northward is:

[tex]p_2 = m_2 v_2 = (4.0 kg)(2.0 m/s)=8.0 kg m/s[/tex]

So the magnitude of the total momentum is:

[tex]p=\sqrt{p_1^2 +p_2^2}=\sqrt{(6.0)^2+(8.0)^2}=10kg m/s[/tex]

Answer:

Oppositely charged particles attract each other, while like particles repel one another. Electrons are kept in the orbit around the nucleus by the electromagnetic force, because the nucleus in the center of the atom is positively charged and attracts the negatively charged electrons.

Explanation:

Answer:

There are three kinds of forces within the atom:

      i) Electromagnetic force of attraction between the electrons and protons  

      ii) Electromagnetic force of repulsion between the protons or weak nuclear force  

      iii) Strong nuclear force between the electrons and protons

Explanation:

Electromagnetic force of attraction:

Electrons revolve in the orbits outside the nucleus. There exists an electromagnetic force of attraction between the electrons and protons. That’s why, electrons do not leave the atom.

Weak nuclear force:

It is an electromagnetic force of repulsion between the protons in the nucleus of the atoms.

Strong nuclear force:

This force is strongest from all the fundamentals forces and exists between the protons and neutrons in the nucleus of atom. This force overcomes the weak nuclear force and does not allow protons to stray away.  

Answer:

247 kJ/mol

Explanation:

Zn(s) + 2HBr(aq) → ZnBr₂(aq) + H₂(g)

First, we need to find the limiting reactant.  And to do that, we need to find the amount of moles of each reactant.

2.50 g Zn * (1 mol / 65.38 g) = 0.03824 mol Zn

0.1000 L * 2.00 mol/L = 0.200 mol HBr

Since 1 mol of Zn reacts with 2 mol of HBr, it is clear that Zn is the limiting reactant.

The amount of heat can be calculated as:

q = (448 J/K) * (21.1 K)

q = 9452.8 J

So the standard enthalpy of reaction is:

ΔH = (9452.8 J) / (0.03824 mol Zn)

ΔH = 247 kJ/mol

The change in electrical potential energy can be calculated using the equation EPE = q x ΔV, where q is the charge of the particle and ΔV is the potential difference. Plugging in the given values, we find that the change in electrical potential energy is 13.50 elementary charge volts.

The change in electrical potential energy of a particle can be calculated using the equation:

EPE = q × ΔV

Where:

Plugging in the given values: q = 3.00 elementary charges and ΔV = 4.50 volts, we can calculate the change in electrical potential energy.

EPE = 3.00 × 4.50 = 13.50 elementary charge volts

Answer:

Sample Response: How does the number of radioactive atoms change over time?

Explanation:

In a lab experiment on radioactive decay, a fitting scientific question could be 'What is the half-life of the given radioactive isotope?' This can be determined through the simulation by measuring the time it takes for half of the simulated atoms to decay.

In this lab experiment revolving around the concept of radioactive decay, an appropriate scientific question could be: 'What is the half-life of the given radioactive isotope?' This question seeks to learn the amount of time it takes for half of an isotope's atoms to decay. During your radioactive decay simulation, you'll be able to measure this by observing how long it takes for half of your simulated atoms to decay.

Using the simulation, one can record the time at regular intervals and count the remaining isotopes. By plotting this data on a graph with time on the x-axis and the number of remaining isotopes on the y-axis, we can see a decay curve form due to the nature of radioactive decay. The half-life is found at the point where half of the isotopes remain.

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Exposing a crystal of a semiconductor to heat or light starts displacing valence electrons, which then move throughout the crystal is true of semiconductors. Correct option is A.

This statement is true. Semiconductors are materials with electrical conductivity that is between that of conductors (such as metals) and insulators (such as rubber or wood). When a semiconductor crystal is exposed to heat or light, it can release or promote electrons from the valence band to the conduction band, creating charge carriers (free electrons and holes). These charge carriers are essential for the operation of semiconductor devices like diodes and transistors, which form the basis of modern electronics.

To know more about semiconductor:

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People have only walked on the Moon, where twelve astronauts have set foot during the Apollo missions between 1969 and 1972. No other planets have been physically explored by humans.

The only planet that people have walked on is Earth's moon. Human exploration of other celestial bodies is quite limited. The United States' Apollo 11 mission was the first to land humans on the Moon, and a total of twelve astronauts have walked on its surface during the Apollo missions that took place between 1969 and 1972. Since then, no human has set foot on any other planet or celestial body.

Final answer:

The statement about elastic collisions conserving total kinetic energy is true. Elastic collisions maintain kinetic energy, whereas inelastic collisions do not. In elastic collisions, kinetic energy may temporarily change forms but is ultimately conserved.

Explanation:

The statement, “In an elastic collision, kinetic energy is transferred from one particle to another, but the total kinetic energy remains constant,” is true. An elastic collision is a type of collision in which no kinetic energy is lost. The total kinetic energy before and after the collision is the same. Although kinetic energy may be transferred between the colliding objects, it is not lost to other forms of energy like thermal or sound energy. A contrasting situation occurs in an inelastic collision, where kinetic energy is not conserved and can be transformed into other forms of energy.

In an elastic collision, even if viewed from different reference frames, such as one where a particle is initially stationary, the total kinetic energy of the system after the collision is equal to the total kinetic energy before the collision. However, during the moment of impact, some kinetic energy may be temporarily stored as elastic potential energy, which then is converted back to kinetic energy as the objects move apart. Hence, the phrase “recovered” is sometimes preferred over “conserved” to describe the kinetic energy in elastic collisions.

A voltmeter is an instrument used to measure the voltage across a component in an electric circuit, and it must be connected in parallel with the component. It operates on the principles of Ohm's law and contains a high-value internal resistor to measure the voltage accurately without significantly influencing the current in the circuit.

A voltmeter is a device specifically designed to measure the voltage across a resistor or any two points in a circuit. When using a voltmeter, it's important to connect it in parallel with the component whose voltage you want to measure. This is to ensure that it measures the full voltage and that its high internal resistance does not significantly alter the current in the circuit. Voltmeters can come in analog form, where a needle moves across a scale, or as a digital voltmeter, which provides a numeric display.

The internal workings of a voltmeter involve it being similar to an ammeter, but with an additional high-value resistor. According to Ohm's law, the current through a resistor is directly proportional to the voltage across it. Hence, the voltmeter can be calibrated to measure volts based on the known value of the internal resistor.

Answer:

13) v = 225,563.9

14) v = 200,000

Answer:

b

Explanation:

took test

Collagen is the protein that holds together the different structures of the body, including skin and bones. This is because the collagen molecule has the ability to mix with many types of substances and minerals, and in the case of bone tissue, the combination of collagen with calcium crystals allows the formation of the hard and rigid structure necessary for healthy bones.

Note that this component is the most abundant in mammals, especially in their skin, and in the specific case of humans, corresponds to approximately [tex]25%[/tex] of the total mass of proteins in our body.

Answer:

the speed of light in glass is 1.52 times smaller than in a vacuum

Explanation:

The speed of light in a medium is given by:

[tex]v=\frac{c}{n}[/tex]

where

c is the speed of light in a vacuum

n is the refractive index of the medium, which is a number always greater than 1.0

From the formula, we see therefore that when light enters a medium, its speed decreases.

In particular, for glass the index of refraction is

n = 1.52

Therefore, this means that the speed of light in glass is 1.52 times smaller than in a vacuum.

intertia hope that helps

Answer:

c)While the amount of neutrinos passing through the Earth does not change much, there is something that changes to you at night. You stop moving and sleep for several hours.  

Think of Neutrinos like rain. During the day you can avoid rain, and run from one dry spot to another(like from a car to a house). At night, however, your asleep, so the rain will hit you for eight hours(if your sleeping outside with no tent for some reason).

Answer:

Make the angle of reflection and the angle of incidence equal.

Explanation:

The law of reflection states that at the point of incidence on a smooth surface, the angle of incidence is equal to the angle  of reflection, The incident ray, the normal and the reflected ray lie on the same plane.

Answer:

B.  Make the angle of reflection and the angle of incidence equal

Explanation:

Answer:

Dark mass or dark matter in our galaxy was discovered from much higher velocities of stars at long distances from the galactic center.

Explanation:

Dark matter is a type of matter, whose composition is unknown and which corresponds to 80% of the matter in the universe. Its name refers to the fact it does not emit or interact with any type of electromagnetic radiation, being completely transparent throughout the electromagnetic spectrum.  

In this sense, it is believed that in our galaxy, the Milky Way, has a great amount of dark matter in  comparison with ordinary matter (known visible matter). Because, like gravity, dark matter can not be observed directly, however its existence is inferred through the movement of the stars and the cosmic dust within the galaxy at zones where is supose there is no matter.

Dark matter was deduced from the high velocities of stars at large distances from the galactic center, which indicated more mass than could be accounted for by visible matter alone.

Dark mass or dark matter in our galaxy was discovered from the much higher-than-expected velocities of stars at great distances from the galactic center. This puzzling phenomenon was first noted by Fritz Zwicky in the 1930s and further studied by Vera Rubin. While the mass of a galaxy was expected to be concentrated at its center, the stars' velocities didn't decrease as anticipated with the square root of the distance from the center; instead, a flat velocity curve was observed. This implied the existence of a significant amount of matter in the galactic halo, which did not emit light and was not directly observable, hence the term 'dark matter.' Rubin's work on spiral galaxies reinforced Zwicky's findings, showing that their outer regions were rotating at similar speeds to their centers, suggesting a discrepancy between visible and actual matter. The presence of dark matter is also confirmed by observations of other electromagnetic (EM) wavelengths—such as radio waves and X-rays—and through the gravitational effects it has on luminous matter, like gravitational lensing.

Answer:

Explanation:

1) Data:

a) W = 875 N

b) Fx = 300 N (right direction = positive)

c) Fp = ?

d) μs = 0.56

e) μk = 0.47

2) Physical principles and formulae:

a) For sliding, Fp ≥ μs × N, where Fp = μs × N is the magnitud of the minimum force need to exert on the crate to make it start sliding

3) Solution:

a) Free body diagram

The balance of the vertical forces implies that the normal force (N) equals the weight (W) of the crate:

b) Fp = μs × N = 0.56 × 875 N = 490 N ← answer

Remarks:

To calculate the minimum force required to make the crate slide, we multiply the coefficient of static friction by the normal force, yielding about 490 N as the minimum required force required to overcome friction and start moving the crate.

The subject of this question is the concept of friction in physics. Specifically, we're looking at how much force is required to overcome static friction and start the motion of a crate on a concrete floor. The static friction force can be determined by multiplying the coefficient of static friction (0.56) with the normal force, which in this case is the weight of the crate (875 N). Therefore, the static friction force would be 0.56 * 875 N = 490 N. This is the force that must be overcome to start sliding the crate. Since the applied force of 300 N is not enough to overcome this friction, the minimum force you need to exert on the crate to start it sliding is about 490 N.

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The answer is:

The correct option is:

C. [tex]4.5x10^{3}N[/tex]

To calculate the force exerted by the pump, we must remember the formula to calculate power, also, we must remember that power means work done in a determined period of time.

We have that power can be calculated by the following equation:

[tex]Power(W)=F*V=N.\frac{m}{s}=\frac{N.m}{s}=1Watt[/tex]

So, we are given the following information:

[tex]Power=3.4x10^{2}W=340W=340\frac{N.m}{s}\\\\V=\frac{7.5x^{-2}m }{s}=\frac{0.075m}{s}[/tex]

Now, substituting and calculating we have:

[tex]Power(W)=F*V[/tex]

[tex]340\frac{N.m}{s}=F*\frac{0.075m}{s}[/tex]

[tex]F=\frac{340\frac{N.m}{s}}{\frac{0.075m}{s}}=4,533N=4.5x10^{3}N[/tex]

Hence, the correct option is:

C. [tex]4.5x10^{3}N[/tex]

Have a nice day!

Answer:

C.  4.5 × 103 newtons on Plato

Breathing is called respiration.

Answer:

respiration

Explanation:

Answer:

12.2 m/s

Explanation:

Initial momentum = final momentum

In the x direction:

(900 kg) (15.0 m/s) = (900 kg + 750 kg) vx

vx = 8.18 m/s

In the y direction:

(750 kg) (20.0 m/s) = (900 kg + 750 kg) vy

vy = 9.09

The magnitude of the velocity is therefore:

v = √(vx² + vy²)

v = 12.2 m/s

Answer:

True

Explanation:

There are several geologic evidences that points to the fact that the earth has undergone different episodes of erosion and mountain building.

These evidences are the key to James Hutton's proposition of the "law of Uniformitarianism". The law which states that " the present is the key to the past and geologic processes that are occurring today have occured in the times past".

Evidences of erosion can be found mostly in sedimentary rock layers. Some of them occur as time gaps/lapses within rock units and they are called unconformity surfaces. Sometimes we can see them as erosional features in sedimentary beds.

Evidences of mountain building can be found in different Orogenic cycles terranes have been placed into. The earth is a dynamic planet and the internal heat engine combines with surface forces to move rocks through different types. Some areas believed to have been raised continental platforms are now stable cratons and shields. Dating rocks from such terrane would reveal several episodes of deformation which corresponds to mountain building cycles..

Heat is energy in transit, that is, transfer of (thermal) energy from one body or system to another.

In other words, when you have two bodies with different temperatures and thermal energy is transferred from one body to another, implying a high speed and kinetic energy in the particles involved, we are talking about heat.

When both bodies or the complete system reaches the thermal equilibrium (they are at the same temperature) the process is over and there is no heat.

the answe would be 80%

Answer:

The efficiency of an engine is 80%.

(A) is correct option.

Explanation:

Given that,

Work done = 576 J

Supplied heat = 720 J

Exhausts of heat = 144 J

We need to calculate the efficiency

Using formula of efficiency

[tex]\eta=1-\dfrac{Q_{2}}{Q_{1}}[/tex]

Where, Q₁ = Supplied heat

Q₂ =  Exhausts of heat

Put the value into the formula

[tex]\eta=1-\dfrac{144}{720}[/tex]

[tex]\eta=0.8\times100[/tex]

[tex]\eta=80\%[/tex]

Hence, The efficiency of an engine is 80%.