Select the sentence that best describes why copper and some other metals are good conductors.

A) Copper atoms have loosely held electrons; this means they can freely move in and out of the nucleus of the atom.
B) Copper atoms have a loosely held free electron in their outer shell that is able to move freely to other atoms.
C) Copper and some other metals have highly active inner shells. This means that electrons can be freely exchanged between shells.
D)Copper has a small number of electrons; this means it can easily shed these electrons and take electrons from other atoms.

The friends have to combine their forces to be greater than the force of the car pushing back on them (3rd law). The car will remain at rest until an outside force acts on it that it is greater than its own (1st). The speed in which the car is being moved is directly related to the amount of force and direction of the kids pushing the car (2nd).

Answer:

1. B

2. D

Explanation:

1. Radioactive decay occurs when a radioactive particle cannot maintain a high energy state due to its own weight. When a radioactive element (eg. Uranium) undergoes radioactive decay, its product/s (following the previous example, Uranium decays into Thorium) are more stable than its reactants.

The question might remain that after Uranium decays to Thorium, where does the extra mass go? The extra mass is released as an alpha particle, and through this process, a lot of energy is released as gamma radiation.

Hence, the answer is:

During radioactive decay, atoms break down releasing particles or energy.

2. The half-life of an element is referred to as:

The length of time taken for one half of the radioactive atoms in a sample to decay.

Hence, since the question states the definition of a half-life, the answer is D.

The correct answer is (b) 'During radioactive decay, atoms break down, releasing particles or energy.' And, the term for the time it takes for one-half of the radioactive atoms in a sample to decay is (d) 'half-life.'

The true statement about radioactive decay is option (b), 'during radioactive decay, atoms break down, releasing particles or energy.' Radioactive decay is a spontaneous process where an unstable atomic nucleus loses energy by emitting radiation, such as an alpha particle, beta particle with neutrino or only a neutrino with case of Electron Capture, or a gamma ray. The other options do not accurately describe this process.

The term referring to the time it takes for one-half of the radioactive atoms in a sample of a radioactive element to decay is option (d), 'half-life.' Half-life is commonly used in nuclear physics and chemistry, and it provides us with a measure of the time scale on which radioactive decay processes occur.

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The gravitational force (weight) of an 8.00 kg object on Earth is 78.4 N. This is calculated using the formula 'w = mg', with 'g' being the Earth's acceleration due to gravity (9.80 m/s²).

The gravitational force exerted on an object by the Earth (also known as the object's weight) can be calculated using the formula w = mg, where m is the mass of the object and g is the acceleration due to gravity. On Earth, the acceleration due to gravity (g) is approximately 9.80 m/s².

For an object with a mass of 8.00 kg, the gravitational force (weight) would be calculated as follows:

w = mg = (8.00 kg)(9.80 m/s²) = 78.4 N

Thus, the Earth exerts a gravitational force of 78.4 N on an object with a mass of 8.00 kg.

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Final answer:

To find the mass of 1.0 m3 of water, we utilize the density of water, which is 1000 kg/m3. By multiplying this with the volume, we determine the mass to be 1000 kg.

Explanation:

To determine the mass of 1.0 m3 of water, we use the known density of water and convert the given volume into the same units for consistency. The density of water is 1 g/cm3, which is equivalent to 1000 kg/m3. Knowing that 1 cubic centimeter (1.0 cm3) of water has a mass of 1.0 × 10-3 kg, and understanding that there are 1,000,000 cm3 in 1 m3, we can find the mass of 1.0 m3 of water.

To calculate the mass, we multiply the density of water by the volume in question. Thus:

Therefore, the mass of 1.0 m3 of water is 1000 kg.

C. An object at rest stays at rest as long as unbalanced forces act on it.

Newton's first law establishes the following:

An object will remain at rest or with uniform rectilinear motion unless an external force acts on it.

Therefore, we have that a case contrary to Newton's first law is:

Unbalanced forces acting on an object at rest, cause the object to remain at rest.

It is false, because if the forces are unbalanced, then the object will not remain at rest because external forces act on the object.

Answer:

A situation that is contrary to Newton's first law of motion is:

An object at rest stays at rest as long as unbalanced forces act on it.

Correct answer choice is :

D) The density changed.

Explanation:

Density is the number of mass placed in a particular volume. The density of an object can vary if either the mass or volume of the object is modified. Fluids, such as water, have a specific density. If an object is thicker than water, it will sink; if it is less thick than water, it will float. Maximum material rises in volume when it gets hotter. For instance, if an iron rod is ignited, it will get longer and thicker and its density will reduce. This occurs because the mass of the rod stays the equivalent, but its volume rises.

To find the final temperature, we can use the equation q = mcΔT, where q is the heat released, m is the mass of the ethylene glycol, c is the specific heat capacity of ethylene glycol, and ΔT is the change in temperature. Plugging in the given values, we can solve for ΔT and then subtract it from the initial temperature to find the final temperature.

To find the final temperature, we can use the equation:

q = mcΔT

Where q is the heat released, m is the mass of the ethylene glycol, c is the specific heat capacity of ethylene glycol, and ΔT is the change in temperature.

Plugging in the given values:

34.8 g × 2.42 J/g °C × ΔT = 783 J

Solving for ΔT:

ΔT = 783 J / (34.8 g × 2.42 J/g °C) = 8.93 °C

To find the final temperature, we can subtract ΔT from the initial temperature:

Final temperature = 22.1 °C - 8.93 °C = 13.17 °C

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The final temperature of the ethylene glycol sample is approximately 32.1°C.

To find the final temperature of the ethylene glycol sample, we can use the specific heat capacity formula:

[tex]\[ q = mc\Delta T \][/tex]

Given:

q = 783 J (heat released),

m = 34.8 g (mass of ethylene glycol),

c = 2.42 J/g°C (specific heat capacity of ethylene glycol),

[tex]\( T_{\text{initial}} = 22.1 \)C[/tex] (initial temperature).

We want to find the final temperature [tex]\( T_{\text{final}} \)[/tex]. First, we rearrange the formula to solve for [tex]\( \Delta T \)[/tex]:

[tex]\[ \Delta T = \frac{q}{mc} \][/tex]

Now we plug in the given values:

[tex]\[ \Delta T = \frac{783 \text{ J}}{(34.8 \text{ g})(2.42 \text{ J/gC})} \] \[ \Delta T = \frac{783}{34.8 \times 2.42} \] \[ \Delta T \approx \frac{783}{84.336} \] \[ \Delta T \approx 9.28 \][/tex]

The change in temperature [tex]\( \Delta T \)[/tex] is approximately 9.28°C. To find the final temperature, we add the change in temperature to the initial temperature:

[tex]\[ T_{\text{final}} = T_{\text{initial}} + \Delta T \] \[ T_{\text{final}} = 22.1 \text{C} + 9.28 \text{C} \] \[ T_{\text{final}} \approx 31.38 \text{C} \][/tex]

Rounding to one decimal place, the final temperature is approximately 31.4°C. However, to match the precision of the given data, we should round to the same precision as the initial temperature:

[tex]\[ T_{\text{final}} \approx 32.1 \text{C} \][/tex]

Therefore, the final temperature of the ethylene glycol sample is approximately 32.1°C.

The magnitude of the total momentum is [tex]\fbox{4.24 kg m/s}[/tex] and the direction is [tex]\bf{south-east}[/tex].

Further Explanation:

The net momentum acting is the sum of all the momentum which is applying on the different bodies considering the direction of action of the momentum. In other words, the net momentum applying on a body is the sum of all the vectors of all the momentum.

The momentum is the vector quantity has some magnitude and unique direction represented in the coordinates system on the x, y and z-axis. It is the related directly to the object mass and object velocity.

Velocity is the vector quantity has some magnitude and some direction represented in the coordinates system on the x, y and z-axis.

Given:

The speed of the two arrows is [tex]30.0 m/s[/tex].

The mass of each arrow is [tex]0.1 kg[/tex].

The first arrow is fired due east and other arrow is fired due south.

Concept:

The expression for the momentum is:

[tex]P=m\vec v[/tex]

Here, [tex]p[/tex] is the momentum, [tex]m[/tex] is the mass of the object and [tex]v[/tex] is the velocity of the object.

The velocity can be represented in the vector form.

The first arrow is fired due east can be written as [tex]30.0{\text{ m/s }}\hat i[/tex] and other arrow is fired due south can be written as [tex]- 30.0{\text{ m/s }}\hat j[/tex].

The total momentum can be expressed as:

[tex]\vec P={m_1}{\vec v_1} + {m_2}{\vec v_2}[/tex]

Here, [tex]\vec P[/tex] is the total momentum, [tex]{\vec v_1}[/tex] and [tex]{\vec v_2}[/tex] are the velocities of the arrows and [tex]{m_1}[/tex], [tex]{m_2}[/tex] are the masses of the arrow.

Substitute [tex]30.0{\text{ m/s }}\hat i[/tex] for [tex]{\vec v_1}[/tex],  [tex]- 30.0{\text{ m/s }}\hat j[/tex] for [tex]{\vec v_2}[/tex], [tex]0.1 kg[/tex] for [tex]{m_1}[/tex] and [tex]0.1 kg[/tex] for [tex]{m_2}[/tex] in the above equation.

[tex]\begin{aligned}\vec P&=\left( {0.1{\text{ kg}}} \right)\left[ {\left( {30.0{\text{ m/s }}\hat i} \right) + \left( { - 30.0{\text{ m/s }}\hat j} \right)} \right]\\&=\left( {0.1{\text{kg}}}\right)\left[ {30.0{\text{ m/s }}\hat i - 30.0{\text{ m/s }}\hat j} \right] \\&=\left( {3\hat i - 3\hat j} \right){\text{ kg}} \cdot {\text{m/s }} \\\end{aligned}[/tex]

Simplify further for the magnitude of the vector.

[tex]\begin{aligned}\left| P \right|&=\sqrt {{3^2} + {3^2}}\\&=\sqrt {9 + 9}\\&=\sqrt {18}\\&=4.24{\text{ kg}}\cdot {\text{m/s}}\\\end{aligned}[/tex]

The direction of the vector can be written as:

[tex]\begin{aligned}\theta&={\tan ^{ - 1}}\left( {\frac{{ - 3}}{3}} \right)\\&={\tan ^{ - 1}}\left( { - 1} \right)\\&=- 45^\circ\\\end{aligned}[/tex]

Therefore, the magnitude of the total momentum is [tex]\fbox{4.24 kg m/s}[/tex] and the negative sign show the direction is [tex]\bf{south-east}[/tex].

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Answer Details:

Grade: Middle school

Subject: Physics

Chapter: Kinematics

Keywords:

Two, arrow, fired, horizontally, same, speed, 30.0 m/s,  ,  , mass, 0.100 kg. One, due, east, south, magnitude, direction, total, momentum, two-arrow system, specify, respect, 4.24 kg m/s, [tex]4.24{\text{ }}\dfrac{{{\text{kg}} \cdot {\text{m}}}}{{\text{s}}}[/tex], south-east.

Answer:

True

Explanation:

just took it

The mechanical advantage of a machine is the ratio of its output force to the input force. The input force here is 35 N and the mechanical advantage is 0.75. Then, the output force is 26.25 N.

The force amplified by utilizing a tool, mechanical device, or machine system is known as mechanical advantage. To achieve the desired output force amplification, the gadget trades off input forces against movement. The law of the lever serves as a paradigm for this. Mechanisms are machine parts made to control forces and motion in this way.

An ideal transmission system does not increase or decrease power. Consequently, the ideal machine is devoid of a power source, frictionless, and built from inflexible materials that do not flex or wear.

Efficiency factors that account for deviations from the ideal are used to represent how well a real system performs in comparison to the ideal.

Mechanical advantage = Fo/Fi

Input force Fi = 35 N

then Fo/Fi = 0.75

then, Fo = 35 × 0.75 = 26.2 N

Therefore, the output force of the machine is 26.2 N

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Final answer:

The mechanical advantage of a machine helps determine the output force given the input force. In this scenario, with a mechanical advantage of 0.75 and an input force of 35 newtons, the machine can lift an output force of 46.67 newtons.

Explanation:

The mechanical advantage of a machine is the ratio of the output force to the input force. In this case, with a mechanical advantage of 0.75 and an input force of 35 newtons, we calculate the output force:

Output Force = Input Force / Mechanical Advantage = 35 N / 0.75 = 46.67 N

Therefore, the machine can lift a load of 46.67 newtons.

The energy of exactly one photon of this microwave radiation is 1.59 × 10⁻²⁴Joule

The term of package of electromagnetic wave radiation energy was first introduced by Max Planck. He termed it with photons with the magnitude is:

[tex]\large {\boxed {E = h \times f}}[/tex]

E = Energi of A Photon ( Joule )

h = Planck's Constant ( 6.63 × 10⁻³⁴ Js )

f = Frequency of Eletromagnetic Wave ( Hz )

The photoelectric effect is an effect in which electrons are released from the metal surface when illuminated by electromagnetic waves with large enough of radiation energy.

[tex]\large {\boxed {E = \frac{1}{2}mv^2 + \Phi}}[/tex]

[tex]\large {\boxed {E = qV + \Phi}}[/tex]

E = Energi of A Photon ( Joule )

m = Mass of an Electron ( kg )

v = Electron Release Speed ( m/s )

Ф = Work Function of Metal ( Joule )

q = Charge of an Electron ( Coulomb )

V = Stopping Potential ( Volt )

Let us now tackle the problem!

Given:

λ = 12.5 cm = 12.5 × 10⁻² m

Unknown:

E = ?

Solution:

[tex]E = h f[/tex]

[tex]E = h \frac{c}{\lambda}[/tex]

[tex]E = 6.63 \times 10^{-34} \frac{3 \times 10^8}{12.5 \times 10^{-2}}[/tex]

[tex]\large {\boxed {E = 1.59 \times 10^{-24} ~ Joule } }[/tex]

Grade: High School

Subject: Physics

Chapter: Quantum Physics

Keywords: Quantum , Photoelectric , Effect , Threshold , Frequency , Electronvolt

The energy of exactly one photon of this microwave radiation is [tex]\boxed{1.584\times10^{-24}\text{ J}}[/tex].

Further Explanation:

Planck’s equation used to solve this question. In the Planck’s equation, the energy of a photon is directly related to the frequency of a photon and inversely related to the wavelength of a photon.

By using Planck’s equation the energy of the one photon can be determined.

The term “Electromagnetic wave radiation energy” was first introduced by the scientist Max Planck.

The light can travel very fast as in the no other thing can travel as faster as light and it’s measures value is approximate [tex]3.0\times{10^8}{\text{ m/s}}[/tex] in vacuum.

The wavelength is the defined as the distance between two consecutive positive peak pointornegative peak point of the wave.

Given:

The wavelength of the energy is [tex]12.5\text{ m}[/tex].

Concept:

The expression for the energy of photon is:

[tex]\boxed{E=\dfrac{{h\cdot c}}{\lambda}}[/tex]

Here, [tex]E[/tex] is the energy of photon, [tex]h[/tex] is the Plank constant, [tex]c[/tex] is the speed of the light and [tex]\lambda[/tex] is the wavelength of the photon.

The value of the Plank constant is [tex]6.6\times{10^{-34}}{\text{ J}\cdot\text{s}}[/tex].

The value of the speed of the light is [tex]3.0\times{10^8}\text{ m/s}[/tex].

Substitute [tex]6.6\times{10^{-34}}{\text{ J}\cdot\text{s}}[/tex] for [tex]h[/tex], [tex]3.0\times{10^8}\text{ m/s}[/tex] for [tex]c[/tex] and [tex]12.5\text{ cm}[/tex] for [tex]\lambda[/tex] in the above equation.

[tex]\begin{aligned}E&=\dfrac{{\left( {6.6 \times {{10}^{ - 34}}{\text{ Js}}} \right) \cdot \left( {3.0 \times {{10}^8}{\text{ m/s}}} \right)}}{{12.5{\text{ cm}}}}\\&=\dfrac{{\left( {6.6 \times {{10}^{ - 34}}{\text{ Js}}} \right) \cdot \left( {3.0 \times {{10}^8}{\text{ m/s}}} \right)}}{{12.5 \times {{10}^{ - 3}}{\text{ m}}}}\\&=1.584 \times {10^{ - 24}}{\text{ J}}\\\end{aligned}[/tex]

Therefore, the energy of exactly one photon of this microwave radiation is [tex]\boxed{1.584 \times {10^{ - 24}}{\text{ J}}}[/tex]

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Answer Details:

Grade: High School

Subject: Physics

Chapter: Photoelectric effect

Keywords:

The energy, photon, microwave, radiation, emits, wavelength ,12.5 cm or 0.125 m, 1.59x10^-23 J, speed of light,  emission, Plank's constant.

Answer:

answer is V

Explanation:

In the solid state of matter, the particles are closest together. Thus, the correct option is B.

The state of matter is one of the distinct forms in which the matter can exist in nature. Four states of matter which are observable in the everyday life are solid, liquid, gas, and plasma states.

Solid state of matter is a state in which the particles are packed tightly in space. The constituent particles can be atoms or the solid particles. The intermolecular distances between the solid particles in the lattice are short and hence the forces of attraction between the molecules are strong. Solids are divided into three broad classes which are crystalline, non-crystalline (amorphous), and quasi-crystalline. Crystalline solids have a very high degree of order in a periodic atomic arrangement of molecules.

Therefore, the correct option is B.

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Answer:

4.5

Explanation:

yes

Answer:

0.07726

Explanation:

Answer:

Nuclear

Explanation:

The force will be "14.4 N".

The given values are:

Mass,

m = 12 kg

Acceleration,

a = 1.2 m/s²

As we know the formula,

→ [tex]Force = Mass\times acceleration[/tex]

By substituting the values, we get

→           [tex]=12\times 1.2[/tex]

→           [tex]= 14.4 \ N[/tex]

Thus the above answer is correct.

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