Based on the second law of thermodynamics why must a machine always be less than 100% efficient?
A.Heat never moves from cold to hot.
B.Heat is never converted completely into mechanical energy.
C.Heat never flows from hot to cold.
D.Entropy never increases.

(a) [tex]a_t = 0.800 m/s^2[/tex]

The tangential acceleration component of the car is simply equal to the change of the tangential speed divided by the time taken:

[tex]a_t = \frac{\Delta v}{\Delta t}[/tex]

This rate of change is already given by the problem, 0.800 m/s^2, so the tangential acceleration of the car is

[tex]a_t = 0.800 m/s^2[/tex]

(b) [tex]a_c = 0.9 m/s^2[/tex]

The centripetal acceleration component is given by

[tex]a_c = \frac{v^2}{r}[/tex]

where

v is the tangential speed

r is the radius of the trajectory

When the speed is v = 3.00 m/s, the centripetal acceleration is (the radius is r = 10.0 m):

[tex]a_c = \frac{(3.00 m/s)^2}{10.0 m}=0.9 m/s^2[/tex]

(c) [tex]1.2 m/s^2, 48.4^{\circ}[/tex]

The centripetal acceleration and the tangential acceleration are perpendicular to each other, so the magnitude of the total acceleration can be found by using Pythagorean's theorem:

[tex]a=\sqrt{a_t^2+a_c^2}=\sqrt{(0.8 m/s^2)^2+(0.9 m/s^2)^2}=1.2 m/s^2[/tex]

and the direction is given by:

[tex]tan \theta =\frac{a_c}{a_t}=\frac{0.9 m/s^2}{0.8 m/s^2}=1.125\\\theta=tan^{-1}(1.125)=48.4^{\circ}[/tex]

where the angle is measured with respect to the direction of the tangential acceleration.

Final answer:

The tangential acceleration component at 3.00 m/s is 0.800 m/s². The centripetal acceleration component is calculated to be 0.900 m/s². The magnitude of the total acceleration is approximately 1.20 m/s² and is found using the vector sum of the tangential and centripetal components.

Explanation:

Understanding Circular Motion and Acceleration

An automobile that is increasing its speed while traveling along a circular path experiences two components of acceleration: tangential acceleration and centripetal acceleration. Given a tangential acceleration of 0.800 m/s² and an instantaneous speed of 3.00 m/s, we can directly state that the tangential acceleration component is 0.800 m/s² as it defines how quickly the vehicle is speeding up along the path.

To find the centripetal acceleration component, we use the formula ac = v² / r, where v is the velocity and r is the radius. Plugging in the values, we calculate ac = (3.00 m/s)² / (10.0 m) = 0.900 m/s².

Finally, the magnitude of the total acceleration can be found by combining these two perpendicular components using the Pythagorean theorem: atotal = √(at² + ac²). Thus, atotal = √(0.8002 + 0.9002) which calculates to approximately 1.20 m/s². The direction of the total acceleration is the direction of the vector sum of the tangential and centripetal accelerations.

Answer:

DCEBA

Explanation:

The velocity at which charged particles will not be deflected by crossed electric and magnetic fields (velocity filter) is determined by the equation v = E/B. For an electric field of 112 kV/m and a magnetic field of 0.82 T, the required velocity is approximately 136585.37 m/s.

The student's question involves determining the velocity of charged particles traveling through crossed electric and magnetic fields without being deflected. This is a classic physics problem that illustrates the concept of a velocity filter. The electric force acting on a particle with charge q in an electric field E is given by Felectric = qE. The magnetic force on a particle moving with velocity v perpendicularly through a magnetic field B is given by Fmagnetic = qvB. For the particle to pass through the fields without deflection, these two forces must be equal in magnitude but opposite in direction.

By setting Felectric equal to Fmagnetic and solving for v, we find the velocity v at which the charged particle will not be deflected:

v = E/B

Substituting the given magnitudes for the electric and magnetic fields (E = 112 kV/m and B = 0.82 T), we calculate:

v = (112 x [tex]10^3[/tex] V/m) / (0.82 T) = approximately 136585.37 m/s

Therefore, the speed at which the particles will not be deflected by the crossed fields is approximately 136585.37 m/s.

I'm pretty sure the answer is false.

The principal advantage of sending electric power across country on very high voltage transmission lines is that it minimizes the power loss due to resistance in conductors.

To answer this question, we must keep in mind the relationship between power, current and resistance, that can be written as:

[tex]P=I^2R[/tex]

So power is dissipated as heat. From the equation, the power loss in the transmission line is proportional to [tex]I^2[/tex]. Another relationship we need to talk about is between power, current and voltage:

[tex]P=VI[/tex]

As you can see, current is inversely proportional to voltage, so if you increase the voltage, then the current decrease and the power loss also decreases.

Answer:

3.68 m/s^2

Explanation:

The period of a pendulum is:

[tex]T=2 \pi \sqrt{\frac{L}{g}}[/tex]

where L is the length of the pendulum and g is the gravitational acceleration.

On Earth, T = 1.50 s and g = 9.8 m/s^2, so we can solve the formula for L to find the length of the pendulum:

[tex]L=g(\frac{T}{2 \pi})^2=(9.8 m/s^2)(\frac{1.50 s}{2\pi})^2=0.56 m[/tex]

The length of the pendulum remains the same on Mars, and since on Mars the period of the pendulum is T = 2.45 s, we can now solve the equation again for g, the gravitational acceleration on Mars:

[tex]g=(\frac{2\pi}{T})^2 L=(\frac{2\pi}{2.45 s})^2 (0.56 m)=3.68 m/s^2[/tex]

The free-fall acceleration on the Mars is 3.68 m/s².

The length of the pendulum on mars is calculated as follows;

[tex]T = 2\pi \sqrt{\frac{L}{g} } \\\\L = \frac{T^2 g}{4\pi^2} \\\\L = \frac{(1.5)^2 \times 9.8}{4\pi ^2} \\\\L = 0.56 \ m[/tex]

The free-fall acceleration on the Mars is calculated as follows;

[tex]g = \frac{L4\pi ^2}{T^2} \\\\g = \frac{0.56 \times 4\pi ^2}{(2.45)^2} \\\\g = 3.68 \ m/s^2[/tex]

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[tex]\lambda_\text{max} = 2.63\times 10^{-9}\;\text{m}[/tex].

The peak emission wavelength of an object depends on its absolute temperature.

[tex]\lambda_\text{max} = \dfrac{2.90\times 10^{-3}}{T}[/tex],

where

For the gas falling into the black hole,

[tex]T = 1.10\times 10^{6}\;\text{K}[/tex].

Apply the formula:

[tex]\lambda_\text{max} = \dfrac{2.90\times 10^{-3}}{T} = \dfrac{2.90\times 10^{-3}}{1.10\times 10^{6}} = 2.64\times 10^{-9}\;\text{m} = 2.64 \;\text{nm}[/tex].

The question mentioned that [tex]\lambda_\text{max}[/tex] is in the X-ray region of the electromagnetic spectrum. According to Encyclopedia Britannica, the wavelength of X-rays range from [tex]10^{-8}\;\text{m}=10\;\text{nm}[/tex] to [tex]10^{-10}\;\text{m} = 0.1\;\text{nm}[/tex], which indeed includes [tex]2.64\times 10^{-9}\;\text{m} = 2.64 \;\text{nm}[/tex].

Your pendulum does a complete swing in 1.9 seconds.  You want to SLOW IT DOWN so it takes 2.0 seconds.

Longer pendulums swing slower.

You need to make your pendulum slightly longer.

If your pendulum is hanging by a thread or a thin string, then its speed doesn't depend at all on the weight at the bottom.  You can add weight or cut some off, and it won't change the speed a bit.  

Final answer:

To make a pendulum swing with a period of 2 seconds instead of 1.9 seconds, the length of the pendulum should be increased.

Explanation:

The subject of this question is Physics, specifically concerning mechanics and the operation of a simple pendulum. To achieve the desired period of 2 seconds per swing for your pendulum, which currently swings once every 1.9 seconds, you should make the pendulum slightly longer. The period of a simple pendulum is determined by the formula T = 2π√(L/g), where T is the period, L is the length, and g is the acceleration due to gravity. Since the period is proportional to the square root of the length, and you wish to increase the period, you should increase L, meaning the length of the pendulum must be extended. Adding mass, removing mass, or shortening the length of the pendulum would not give you the desired period.

The person who came up with this conjecture was Albert Einstein

Answer:

John Archibald Wheeler

Explanation:

the famous conjecture  "space, time, and matter" is given by John Archibald Wheeler .

Albert Einstein stated that the fourth dimension is space time.

But  John Archibald Wheeler  was the physicist who later collaborator of Albert Einstein and work on the mission to achieve unified field theory.

John Archibald Wheeler stated that space time tells matter how to move and matter curves space time.

1.) independent

2.) dependent

3.) gap width

Answer:

1. Independent

2. Dependent

3. width of barrier line

Explanation:

1. The independent variable is the one that does not depend on any variable and it can be set to any value. Thus, wavelength is Independent variable.

2. The dependent variable is the one which depends upon the value of other variables, like diffraction angle here depends upon the wavelength. Thus, diffraction angle is Dependent variable.

3. The parameter kept constant of the barrier is the width of barrier line. Multiple lines are drawn on diffraction grating to provide obstruction to wave. Their width is always kept constant.

Correct options:

- Blue light has a wavelength of 750 nm, the longest wavelength of visible light, and red has a wavelength of 500 nm. --> FALSE. It's actually the opposite: blue light has a wavelength of approx. 500 nm, while red has a wavelength of 750 nm, the longest wavelength of visible light.

- Light is electromagnetic radiation, a type of energy embodied in oscillating electric and magnetic fields. --> TRUE. Electromagntic radiation is a type of transverse waves, consisting of electric and magnetic fields oscillating perpendicularly to each other.

- The units of frequency are distance per second. --> FALSE. Frequency is measured in Hertz (Hz), which corresponds to 1/seconds ([tex]s^{-1}[/tex].

- The more closely spaced the waves, that is, the longer the wavelength, the more energy there is. --> FALSE. The energy of an electromagnetic wave is inversely proportional to the wavelength:

[tex]E=\frac{hc}{\lambda}[/tex]

that means, the longer the wavelength, the less energy there is.

- Grass appears green because it reflects primarily the wavelength associated with green light and absorbs the others. --> TRUE. The color of the objects as we see them corresponds to the color they reflect, while all the other colors are absorbed by the object.

- Light in a vacuum travels at 3.00×108mph. --> FALSE. The units are wrong: the speed of light in a vacuum is [tex]3.00\cdot 10^8 m/s[/tex].

- Electromagnetic radiation can be characterized by wavelength, amplitude, and frequency. --> TRUE. Wavelength is the distance between two consecutive crests, amplitude is the maximum displacement of the wave relative to the equilibrium position, frequency is the number of oscillations per second.

- The presence of a variety of wavelengths in white light is responsible for the way we perceive colors in objects. --> TRUE. White light consists of many different colors, and depending on which of them are absorbed/reflected by the objects, we perceive them in different ways.

Answer: the question is what are the colors of visible light.

Explanation: red, orange, yellow, green, blue, indigo, and violet.

The purpose of this titration is to give you a rough idea how much titrant is needed before you begin the actual titration.

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Answer:The purpose of this titration is to give you a rough idea how much titrant is needed before you begin the actual titration. Use a pipet to deliver a known amount of the analyte to the appropriate container (usually an Erlenmeyer flask) which has been cleaned and rinsed with distilled water.

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Heterogenous mixture. Meaning it is a mixture of many different things in the air, other than just one thing (homogenous).

Smog is a heterogeneous mixture.

Explanation:

The mixtures are classified into two type depending upon their uniformity. When the mixture is uniformly distributed, it is called as a homogeneous mixture and when the mixture is spread in a uneven manner, it is called as an heterogeneous mixture. Smog is a chemical reaction which occurs when rays of light reacts with nitrogenous oxides. It is also a type of air pollution.

Answer:

Impulse is equal to the change in momentum

Explanation:

The impulse exerted on an object is given by:

[tex]I=F \Delta t[/tex]

where

F is the force exerted on the object

[tex]\Delta t[/tex] is the duration of the collision

We can re-write the force F by using Newton's second law, F = ma:

[tex]I=(ma)\Delta t[/tex]

where m is the mass of the object and a its acceleration. Now we can rewrite the acceleration as ratio between the change in velocity and the time elapsed:

[tex]I=m \frac{\Delta v}{\Delta t}=m \Delta v[/tex]

and the product [tex]m \Delta v[/tex] is the change in momentum of the object.

Impulse is equal to the change in momentum. It is calculated as the product of the net force and the time interval during which the force acted on an object.

Conceptually, impulse signifies the effect of a net force that acts upon an object to change its state of motion. Impulse can be expressed mathematically as the product of the average force and the time interval during which the force acted on an object. This mathematical representation can be written as J = Δp = FnetΔt, where J represents impulse, Δp is the change in momentum, Fnet is the net force, and Δt is the time interval. Note that when force is variable, the total impulse is computed as the sum (integral) of all infinitesimal impulses.

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1) When you look toward the Galactic Center with your eye, you see a long, thin strip. This suggests a disk seen edge-on, rather than a ellipsoid or another shape. We can also detect the bulge at the center. Since we see spiral galaxies which are disks with central bulges, this is a bit of a top.

Final answer:

Astronomers believe the Milky Way is a spiral galaxy because its rotational motion, gas, color, and dust are characteristics of spiral galaxies, and it matches the observable structures of other known spiral galaxies. Our position within one of its spiral arms helps us observe these features. The differential rotation of the Milky Way creates and maintains the spiral arm structure over time.

Explanation:

Astronomers conclude that the Milky Way is a spiral galaxy for multiple reasons. The observable band of light from Earth, known as the Milky Way, is the disk of our galaxy which exhibits the characteristics of a typical spiral galaxy. When observing the velocity of stars and gas, we see rotational motion typical of spiral galaxies. Moreover, the presence of gas, distinctive colors, and dust within our galaxy align with those found in other known spiral galaxies.

Our Solar System is situated within one of these spiral arms, giving us a vantage point from which we observe most of the stars. To better understand the structure of the Milky Way, astronomers compare it to visible spiral galaxies, such as the Andromeda galaxy. These comparisons have been invaluable for grasping the Milky Way's properties.

One of the Milky Way’s defining features is its differential rotation, which causes its material to stretch into the distinct spiral arms we theorize it has. Despite this differential rotation, which one might expect would wind the arms tighter over billions of years, the arms maintain their spiral structure, suggesting that there are additional dynamics at play to keep them from winding up too tightly.

Answer:

0.1 kg

Explanation:

The kinetic energy of an object is given by:

[tex]K=\frac{1}{2}mv^2[/tex]

where

m is the mass of the object

v is the speed of the object

The momentum of an object is given by

[tex]p=mv[/tex]

which is the product of mass and speed.

We can combine the two equations to get an expression that relates the kinetic energy K to the momentum p:

[tex]K=\frac{1}{2}m(\frac{p}{m})^2=\frac{p^2}{2m}[/tex]

In this problem, we know

[tex]K=1000 J[/tex] is the kinetic energy

[tex]p=200 kg m/s[/tex]

So we can solve the formula for m to find the mass of the projectile:

[tex]m=\frac{p^2}{2K}=\frac{(200 kg m/s)^2}{2(1000 J)}=20 kg[/tex]

The mass of the projectile object that has a kinetic energy of 1000 J and momentum of 200 kgm/s is 20 kg.

When a body of mass (m) and moving with the velocity (u) then the body possesses the energy and this energy is called kinetic energy.

A projectile is launched with a momentum of 200 kg m/s and 1000 J of kinetic energy.

We know that the equation of kinetic energy is given by

[tex]\rm KE = \dfrac{1}{2} mu^2[/tex]...1

We know the momentum is given by

[tex]\rm P = mu\\\\u = \dfrac{p}{m}[/tex]..2

From equations 1 and 2, we have

[tex]\rm KE = \dfrac{1}{2} m(\dfrac{P}{m})^2\\\\KE = \dfrac{1}{2m} (P)^2\\\\m \ \ = \dfrac{P^2}{2*KE}[/tex]

Put the value of kinetic energy (KE) and momentum (P), we have

[tex]\rm m = \dfrac{P^2}{2*KE}\\\\\\m = \dfrac{200^2}{2*1000}\\\\\\m = \dfrac{40000}{2000}\\\\\\m = 20[/tex]

The mass of the projectile object is 20 kg.

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Endothermic reactions are chemical processes that absorb heat. Examples are photosynthesis, melting ice, sweating, baking bread, and the use of cold pack for injuries.

Endothermic reactions are chemical processes that absorb heat from the surroundings, the opposite of exothermic reactions which release heat. Here are five examples of endothermic reactions that may occur around you:

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Answer:

A) heat

Explanation:

As kinetic energy increases, so does the heat energy produced. The faster the molecules move, the more heat that is generated.

As the kinetic energy of an object increases, so does the heat energy, light energy, atomic energy or potential energy may be produced.

Energy cannot be created or destroyed, according to the rule of conservation of energy. However, it is capable of change from one form to another. An isolated system's total energy is constant regardless of the types of energy present. The law of energy conservation is adhered to by all energy forms. The law of conservation of energy essentially says that

The total energy of the system is conserved in a closed system, also known as an isolated system.

Example of change of kinetic energy to heat energy: rubbing your hands together.

Example of change of kinetic energy to light energy: Scratching two stones with each other.

Example of change of kinetic energy to atomic energy: Fission in nuclear reactor.

Example of change of kinetic energy to potential energy: Blowing of balloon.

Hence, all options are correct.

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The pattern on the right side is caused by the interference of waves. When two or more waves come into contact, they can interact and produce a pattern due to constructive or destructive interference. In this case, the disappearing part of the wave is the result of destructive interference.

This phenomenon is known as interference. Interference occurs when two or more waves come into contact and interact with each other. In the case of the waves passing through the barrier, the interference results in a pattern on the right side where part of the wave tends to disappear. This pattern is caused by the superposition of the waves, where the peaks of one wave coincide with the troughs of another wave, leading to destructive interference and a reduction in the amplitude of the wave in certain regions.

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Answer:

(2) 1.60 times 10^-17 C

Explanation:

The value of one elementary charge is

[tex]1 e = 1.60\cdot 10^{-19} C[/tex]

In this problem, we have 100 elementary charges: to find how many Coulombs it corresponds, we have to set up the following proportion

[tex]1 e: 1.60\cdot 10^{-19}C= 100 e : x[/tex]

And solving for x, we find

[tex]x=\frac{(1.6\cdot 10^{-19}C)(100 e)}{1 e}=1.6\cdot 10^{-17}C[/tex]

So, the correct answer is

(2) 1.60 times 10^-17 C

Answer:

1966 J

Explanation:

The work done by the hose on the balloon is equal to the elastic potential energy stored in it:

[tex]W=U=\frac{1}{2}kx^2[/tex]

where

k = 130 N/m is the spring constant

x = 5.50 m is the stretching of the hose before it is being released

If we substitute these numbers into the equation, we find:

[tex]W=U=\frac{1}{2}(130 N/m)(5.50 m)^2=1966 J[/tex]

So, the work done is 1966 J.

(a) 0.29 s

If you yell, your voice will reach your friend by travelling as a sound wave through the air.

The speed of sound in air is

v = 340 m/s

while the distance to be covered is

d = 100 m

So, the time taken is

[tex]t=\frac{d}{v}=\frac{100 m}{340 m/s}=0.29 s[/tex]

(b) 0.24 s

In this case, the voice is transmitted as a radio wave (electromagnetic wave) to the satellite and then back.

The speed of electromagnetic waves is the speed of light:

[tex]c=3\cdot 10^8 m/s[/tex]

while the distance the wave has to cover is twice the distance between the ground and the satellite:

[tex]d=2 \cdot 36000 km=72000 km=7.2 \cdot 10^7 m[/tex]

So, the time taken is

[tex]t=\frac{d}{c}=\frac{7.2\cdot 10^7 m}{3\cdot 10^8 m/s}=0.24 s[/tex]

(c) 81.6 m

In order for the two delays to be equal, the distance between you and your friend (d') must satisfy the equation

[tex]\frac{d'}{v}=\frac{d}{c}[/tex]

where on the left is the time taken by the sound to travel through the air, while on the right is the time taken by the radio wave to travel back and forth from the satellite.

Solving the equation for d',

[tex]d'=v\frac{d}{c}=(340 m/s)\frac{7.2\cdot 10^7 m}{3\cdot 10^8 m/s}=81.6 m[/tex]

Answer:

volume;mass

Explanation:

Answer:

Electrons in an atom make up most of the volume of the atom, while the protons and neutrons make up nearly all of the mass of the atom.

Explanation:

Most of the mass of an atom comes from its nucleus, in which protons and neutrons are found, both of these particles have approximately the same mass.

The atom is also composed of electrons rotating in orbitals around the nucleus, and they have little mass compared to a proton or neutron. But despite being much lighter than the particles in the nucleus, the electron cloud occupies most of the space or volume of the atom.

1) [tex]3.38\cdot 10^6 m/s[/tex]

When both the electric field and the magnetic field are acting on the electron normal to the beam and normal to each other, the electric force and the magnetic force on the electron have opposite directions: in order to produce no deflection on the electron beam, the two forces must be equal in magnitude

[tex]F_E = F_B\\qE = qvB[/tex]

where

q is the electron charge

E is the magnitude of the electric field

v is the electron speed

B is the magnitude of the magnetic field

Solving the formula for v, we find

[tex]v=\frac{E}{B}=\frac{1.56\cdot 10^4 V/m}{4.62\cdot 10^{-3} T}=3.38\cdot 10^6 m/s[/tex]

2) 4.1 mm

When the electric field is removed, only the magnetic force acts on the electron, providing the centripetal force that keeps the electron in a circular path:

[tex]qvB=m\frac{v^2}{r}[/tex]

where m is the mass of the electron and r is the radius of the trajectory. Solving the formula for r, we find

[tex]r=\frac{mv}{qB}=\frac{(9.1 \cdot 10^{-31} kg)(3.38\cdot 10^6 m/s)}{(1.6\cdot 10^{-19} C)(4.62\cdot 10^{-3}T)}=4.2\cdot 10^{-3} m=4.1 mm[/tex]

3) [tex]7.6\cdot 10^{-9}s[/tex]

The speed of the electron in the circular trajectory is equal to the ratio between the circumference of the orbit, [tex]2 \pi r[/tex], and the period, T:

[tex]v=\frac{2\pi r}{T}[/tex]

Solving the equation for T and using the results found in 1) and 2), we find the period of the orbit:

[tex]T=\frac{2\pi r}{v}=\frac{2\pi (4.1\cdot 10^{-3} m)}{3.38\cdot 10^6 m/s}=7.6\cdot 10^{-9}s[/tex]

What is the speed of a beam of electrons when the simultaneous influence of an electric field of 1.56×104V/m and a magnetic field of 4.62×10−3T, with both fields normal to the beam and to each other, produces no deflection of the electrons?

Express your answer in meters per second.

v =

3.38×106  

m/s

Previous Answers

Correct

Part BPart complete

When the electric field is removed, what is the radius of the electron orbit?

Express your answer in meters.

R =

4.16×10−3  

m

Previous Answers

Correct

Correct answer is shown. Your answer .0041 m was either rounded differently or used a different number of significant figures than required for this part.

Part CPart complete

What is the period of the orbit?

Express your answer in seconds.

T =

7.74×10−9  

s

Previous Answers

Correct

Correct answer is shown. Your answer 7.6⋅10−9 = 7.6×10−9 s was either rounded differently or used a different number of significant figures than required for this part.

Answer:

3. Wg is positive and WT is negative.

Explanation:

The work done by a force is given by:

[tex]W=Fdcos \theta[/tex]

where

F is the force

d is the displacement of the object

[tex]\theta[/tex] is the angle between the directions of F and d

This means that:

- When force and displacement are parallel, [tex]\theta=0, cos \theta=+1[/tex], so the work done is positive

- When force and displacement are anti-parallel, [tex]\theta=180^{\circ}, cos \theta=-1[/tex], so the work done is negative

In this case, the crane is moving downward. The force of gravity is also downward, while the tension in the cable is upward. so we have:

- Wg is positive, because gravity is parallel to the displacement

- Wt is negative, because the tension is opposite to the displacement

The work done by gravity, Wg, when a steel girder is lowered by a crane with constant speed is positive, while the work done by the tension in the cable, WT, is negative. This is due to the direction of these forces in relation to the girder's movement. Hence, the correct statement is 'Wg is positive and WT is negative'.

The student question is about the work done by gravity (Wg) and the work done by the tension in the cable (WT) as a crane lowers a steel girder with constant speed. To understand this, we must adopt Newton's laws and the principle of work-energy theorem. When the girder is lowered, being pulled towards the ground, the work done by gravity, Wg, is considered positive as the displacement is in the same direction of the force. On the contrary, the work done by the tension in the cable, WT, is negative. This is because the tension in the cable acts opposite to the direction of displacement, counteracting the force of gravity to control the descent of the girder.

Therefore, the correct option is 3. Wg is positive and WT is negative. This is because of the directional components of these forces acting on lowering the girder. Such forces and their interactions illustrate the basic principles of physics, such as Newton's laws and the work-energy theorem which inform on how objects move and interact.

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(a) 9305 J

Let's start by finding the acceleration of the spelunker, through the following equation:

[tex]v^2-u^2=2ad[/tex]

where

v = 2.40 m/s is the final velocity

u = 0 is the initial velocity

a is the acceleration

d = 11.0 m is the distance covered

Solving for a,

[tex]a=\frac{v^2-u^2}{2d}=\frac{(2.40 m/s)^2-0}{2(11.0 m)}=0.26 m/s^2[/tex]

Now we can find the force lifting the spelunker. The equation for Newton's second law applied to the spelunker is:

[tex]F-mg = ma[/tex]

where

F is the lifting force

m = 84.0 kg is the mass of the spelunker

g = 9.81 m/s^2 is the acceleration due to gravity

a = 0.26 m/s^2 is the acceleration

Solving for F,

[tex]F=m(a+g)=(84.0 kg)(0.26 m/s^2+9.81 m/s^2)=845.9 N[/tex]

And now we can finally find the work done on the spelunker by the lifting force F:

[tex]W=Fd=(845.9 N)(11.0 m)=9305 J[/tex]

(b) 9064 J

In this case, the speed is constant, so the acceleration is zero. So Newton's second Law becomes

[tex]F-mg=0[/tex]

From which we find

[tex]F=mg=(84.0 kg)(9.81 m/s^2)=824.0 N[/tex]

And so the work done is

[tex]W=Fd=(824.0 N)(11.0 m)=9064 J[/tex]

(c) 8824 J

The acceleration of the spelunker here is given by

[tex]v^2-u^2=2ad[/tex]

where

v = 0 is the final velocity

u = 2.40 m/s is the initial velocity

a is the acceleration

d = 11.0 m is the distance covered

Solving for a,

[tex]a=\frac{v^2-u^2}{2d}=\frac{0-(2.40 m/s)^2}{2(11.0 m)}=-0.26 m/s^2[/tex]

Newton's second law applied to the spelunker is:

[tex]F-mg = ma[/tex]

where

F is the lifting force

m = 84.0 kg is the mass of the spelunker

g = 9.81 m/s^2 is the acceleration due to gravity

a = -0.26 m/s^2 is the acceleration

Solving for F,

[tex]F=m(a+g)=(84.0 kg)(-0.26 m/s^2+9.81 m/s^2)=802.2 N[/tex]

And now we can finally find the work done on the spelunker by the lifting force F:

[tex]W=Fd=(802.2 N)(11.0 m)=8824 J[/tex]

To determine the volume of N₂ gas at new conditions, use the combined gas law, converting temperatures to Kelvin and keeping volume units consistent. Solve for V2 using initial conditions of STP and final conditions of 155 °C and 368 torr.

To find the volume of N₂ gas at 155 °C and a pressure of 368 torr, we first need to apply the Ideal Gas Law, but since we are comparing two states of the same amount of gas, we use the combined gas law which is P1V1/T1 = P2V2/T2. Remember that the temperature needs to be in Kelvin and the volume can stay in its units as long as they are consistent.

First, convert 155 °C to Kelvin: 155 + 273 = 428 K and note that STP conditions are 0 °C (which is 273 K) and 760 torr.

Then, use the formula with our known values:
P1 = 760 torr (standard pressure),
V1 = 746 ml (initial volume),
T1 = 273 K (standard temperature),
P2 = 368 torr (final pressure),
T2 = 428 K (final temperature).

Plugging the values into the equation and solving for V2 gives us the volume of gas at the new conditions. Make sure to perform all necessary conversions so that units are consistent (Kelvin for temperature, volume in mL or L, and pressure in torr or atm).

To find the new volume of the nitrogen gas, we use the combined gas law. After plugging in the given values and solving, the nitrogen gas will occupy approximately 3520 mL at 155°C and 368 torr.

To solve this problem, we will use the combined gas law which relates pressure, volume, and temperature of a gas. The combined gas law is given by:

Given data:

Now, we use the combined gas law to find the final volume ([tex]V_2[/tex]):

Thus, the nitrogen gas will occupy 3520 mL at 155°C and 368 torr.

The "legs" of a right triangle form a right angle, so they're perpendicular.

My guess for this one would be; 400 N

My reasoning would be; it starts at 0 on both X and Y, if you need to get to 1.00 meters thats 4/4. 1/4 of 1.00 is .25, and on .25 its on 100 so multiply it by 4 to make 1.00 and you get 400 N

Answer:

The needed force is 400 N.

Explanation:

We need to calculate the force for 1.00 m string

According to graph,

The force applied for stretch from 0.10 to 0.15 is 20 N.

0.10-0.15 = 0.05 m

So, the force applied is 20 N for 0.05 m.

For stretch 0.05 m = 20 N

For stretch 1 m = [tex]\dfrac{20}{0.05}= 400\ N[/tex]

Hence, The needed force is 400 N.

Final answer:

When the distance between two stars decreases by one-third, the gravitational force between them increases by a factor of 9, according to the inverse square law.

Explanation:

When the distance between two stars decreases, the force between them is goverened by the inverse square law. This law states that the gravitational force between two objects is inversely proportional to the square of the distance between their centers.

For example, if the distance between two stars decreases to one-third of its original distance, the calculation to find the new force is as follows:

Let F be the original force.

Let the original distance be d.

If the distance decreases to (1/3)d, according to the inverse square law, the new force will be F' = F × (⅓)^-2 = F × (3/1)^2 = 9F.

Thus, when the distance between the two stars decreases by one-third, the force will increase by a factor of 9.