In the 1950s, an experimental train, which had a mass of 2.50X10^4 kg, was powered across a level track by a jet engine that produced a thrust of 5.00X10^5 N for a distance of 509m.
a. Find the work done on the train
b. Find the change in Kinetic energy.
c. Find the final kinetic energy of the train if it started from rest.
d. Find the final speed of the train if there had been no fricion. ...?

C is the correct answer but the best possible answer is that work is done when a force is imposed on an object and the object moves in the same direction as the force

Hope this helps!

Work in physics is done when a force is applied and causes displacement in the direction of the force. The correct answer is that for work to be done, a force must be transferred and the object must move.

In physics, work is defined as the transfer of energy to an object by applying a force that causes the object to move.

The correct answer to what determines whether work is being done is C: In order for work to be done a force must be transferred and the object must move.

For work, in the scientific sense, to occur, a force must be exerted and there must be displacement in the direction of the force.

Formally, the work done is the product of the component of the force in the direction of the displacement and the distance through which the force acts, which is articulated in the equation W = | F | (cosθ) | d |, where W is work, F is the magnitude of the force, cosθ is the cosine of the angle between the force vector and the displacement vector, and d is the displacement.

Answer:

r = [3 * (pAl/MAl)]/(4 * pi)]^1/3

r = [3 * (pFe / MFe)]/(4 * pi)]^1/3

Explanation:

In the equilibrium state, aluminum and iron have the same mass. From the density equation and solving for the mass we have:

Mass = density/volume

MFe = pFe/V

MAl = pAl/V

In equilibrium, we have that MFe = MAl

Solving for the volume:

MFe = pFe/V

V = pFe/MFe

MAl = pAl/V

V = pAl/MAl

The equation for the volume of a sphere is equal to:

V = (4 * pi * r^3)/3

Replacing the volume of both iron and aluminum, we have:

V = (4 * pi * r^3)/3

r = [(3 * V)/(4 * pi)]^1/3

r = [3 * (pAl/MAl)]/(4 * pi)]^1/3

r = [3 * (pFe/MFe)]/(4 * pi)]^1/3

Answer:

Hydro energy

Explanation:

Answer:

hydro energy would be the answer.

Explanation:

To describe velocity, you need to know speed and direction. Option (a) is correct.

You need to understand direction and speed in order to define velocity. The magnitude (speed) and direction of an object's motion are both included in the vector variable known as velocity. An object's speed is represented by the speed component and its direction by the direction component. Therefore, both speed and direction must be taken into account in order to adequately represent velocity.

Speed (how quickly an object is traveling) and direction (the path it is taking) are two essential components of velocity. These two elements work together to provide a precise description of an object's velocity.

Hence, To describe velocity, you need to know speed and direction. Option (a) is correct.

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The statement that only electrons orbit the nucleus of an atom is false.

The statement that only electrons orbit the nucleus of an atom is false. In an atom, there are several subatomic particles, including protons and neutrons, that also make up the nucleus. Electrons, on the other hand, are found in energy levels or orbitals outside the nucleus. These energy levels determine the arrangement and behavior of electrons in an atom.

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Final answer:

The acceleration of the two boxes on a frictionless surface is 1.67 m/s². The force between the two boxes, as calculated using Newton's second law of motion, is 13.36 N.

Explanation:

To find the acceleration of the two boxes on a frictionless surface that are in contact with each other, we can use Newton's second law of motion, which states that the acceleration of an object is directly proportional to the net force acting on the object and inversely proportional to its mass (F = ma).

The first box has a mass of 7 kg and the second box has a mass of 8 kg. The total mass of the system is therefore 7 kg + 8 kg = 15 kg. When a 25 N force is applied to the 7 kg box, and since there is no friction, this force is the net force acting on the system of both boxes.

The formula for acceleration is a = F/m, where F is the net force and m is the total mass. Substituting our values, we have a = 25 N / 15 kg, which gives an acceleration (a) of 1.67 m/s² (to two decimal places).

Now to find the force between the boxes, we consider that the same acceleration applies to both because they are in contact. The force that the 7 kg box exerts on the 8 kg box is equal to the mass of the 8 kg box times the acceleration. Using F = ma again, we get F = 8 kg x 1.67 m/s², which gives us a force (F) of approximately 13.36 N.

Answer:

Electric current is the flow of a charge

Explanation:

Electric current is defined as the flow of electric charges. Mathematically, it is given by :

[tex]I=\dfrac{q}{t}[/tex]

Where

q = electric charge

t = time interval

The SI unit of electric current is ampere. It is denoted by letter A. According to Ohm's law, electric current can be given by  voltage divided by resistance of the circuit. Hence, the correct option is (c) " Electric current is the flow of a charge ".                      

Answer:

392.8 m

Explanation:

Horizontal velocity is 38.89 m/s

Vertical distance y =0.5 km = 500 m

First calculate the time in which the package will hit the ground.

Use the second equation of motion

[tex]y = u t + 0.5 at^2[/tex]

[tex]500 = 0 + 0.5 (9.8) t^2[/tex]

t =10.1 s

Horizontal distance covered in the same time is

x = ut = (38.89) (10.1) = 392.8 m

The plane will cover the same horizontal distance in the time in which the package hits the ground.

While the movie The Martian portrays a strong windstorm forcing Mark Watney to move away from the HAB, in reality, Mars' thin atmosphere makes such forceful windstorms unlikely. Watney's movements away from the HAB are more a result of seeking survival solutions than escaping the aftermath of a storm. The movie creatively explores human survival and ingenuity on Mars, though it takes liberties with Martian atmospheric science.

In the movie The Martian, the protagonist Mark Watney, played by Matt Damon, is stranded on Mars due to a strong windstorm that forces his crew to evacuate, thinking him dead. This premise raises intriguing questions about the possibility of such windstorms on Mars. Although the depiction of Mars in the film is largely accurate, astronomers have pointed out that the Martian atmosphere is too thin for windstorms to possess the force shown in the movie. Thus, the scenario dramatized in the film, including the necessity for Watney to move away from the HAB (Habitat Module), stems more from creative license than from scientific accuracy. However, this fictional setup serves as a backbone for exploring human ingenuity and survival in extraterrestrial environments.

Watney's decision to move away from the HAB at different points in the story is driven more by narrative needs and his strategies for survival, such as finding a way to communicate with Earth or traveling to the Ares 4 landing site, rather than by the windstorm's aftermath. The challenges Watney faces and overcomes highlight a powerful message about resilience and the capacity to innovate under dire circumstances.

By definition we have to:

Applied force: It is the external force that acts directly on a body.

Therefore, we can say that if you have an object and push it towards yourself, you are exerting an external force on the object.

This external force was not acting on the object previously, therefore, it is a force that you are applying at that moment.

Answer:

you exert an Applied Force on an object when you pull it towards you

A. Applied Force

Answer:

Infrared waves

Explanation:

If electromagnetic waves are arranged in increasing order of wavelengths then the order is given as following

1. Gamma rays

2. X rays

3. Ultraviolet waves

4. Visible light

5. Infrared waves

6. micro waves

7. Radio waves

So here we can say that increasing the wavelength means the energy is decreasing as we move towards higher wavelength.

So from above order the larger wavelength with respect to the visible light is given as "Infrared waves"

Correct answer choice for question 1 is :

C) Iron magnet

Explanation:

Materials which will be magnetic , that are also those that are powerfully drawn to a magnet, as known as magnetism. These embrace iron, nickel, cobalt, some alloys of rare-earth metals, and a few present minerals like static magnet. Magnets attract iron thanks to the influence of their magnetic flux upon the iron. once exposed to the magnetic flux, the atoms begin to align their electrons with the flow of the magnetic flux, that makes the iron magnetic likewise. This, in turn, creates an attraction between the 2 magnetic objects.

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Correct answer choice for question 7 is :

D) Domains

Explanation:

Magnetism could be a category of physical phenomena that are mediate by magnetic fields. Electrical currents and therefore the magnetic moments of elementary particles bring about to a magnetic flux, that acts on alternative currents and magnetic moments. Iron filings interested in a horseshoe magnet show the magnetic flux. Magnetism is one side of the combined magnetic force force. It refers to physical phenomena arising from the force caused by magnets, objects that turn out fields that attract or repel alternative objects.

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Correct answer choice for question 8 :

D) Domains

Explanation:

Magnetism could be a category of physical phenomena that are mediate by magnetic fields. Electrical currents and therefore the magnetic moments of elementary particles bring about to a magnetic flux, that acts on alternative currents and magnetic moments. Iron filings interested in a horseshoe magnet show the magnetic flux. Magnetism is one side of the combined magnetic force force. It refers to physical phenomena arising from the force caused by magnets, objects that turn out fields that attract or repel alternative objects.

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A sled is pushed along an ice-covered lake. It has some initial velocity before coming to rest in 15m. It took 23 seconds before the sled and rider came to a rest. If the rider and sled have a combined mass of 52.5 kg, the magnitude, and direction of the force - 2.98 N which is called friction.

Given:

Time t = 15 s

distance d = 23 m

mass = 52.5

As we know the formula,

[tex]Solution:\\\\\\bar v = \frac{d}{t}\\\\ = \frac{15}{23}\\ \\ = 0.65 \ m/s\\\\According\ to\ the\ question,\\v_f =0\\then,\\2 \bar v = v_i\\2(0.65)=v_i\\v_i=1.3 \ m/s\\u = Initial\ velocity,\\v = Final\ Velocity,\\a = acceleration\\\\According\ to\ the\ second\ law\ of\ motion\\Force = m\times a\\ = (-.057)\times 52.5\\ = -2.97 \ N[/tex]

Thus, F is taken to be negative. So, the stopping force is -2.97 N and this force is the frictional force and its direction is opposite to that of motion.

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Final answer:

Instantaneous speed and instantaneous velocity are related but different concepts in physics. The instantaneous speed refers to the speed of an object at a specific instant in time, while instantaneous velocity includes both magnitude and direction. If the instantaneous speed of an object remains constant, its instantaneous velocity can change if there is a change in direction of motion. Similarly, if the instantaneous velocity remains constant, the instantaneous speed can change if the object accelerates or decelerates.

Explanation:

Instantaneous speed and instantaneous velocity are related but different concepts. Instantaneous speed refers to the speed of an object at a specific instant in time, while instantaneous velocity refers to the velocity of an object at a specific instant in time, including both magnitude and direction. Although the instantaneous speed of an object can remain constant, its instantaneous velocity can change if there is a change in direction of motion. For example, if an object is moving in a circular path at a constant speed, its instantaneous speed remains the same, but its instantaneous velocity constantly changes because the direction of motion is constantly changing.

Similarly, if the instantaneous velocity of an object remains constant, its instantaneous speed can still change if the object speeds up or slows down. This can occur when an object experiences an acceleration or deceleration. For example, if a car is moving at a constant velocity of 50 km/h and suddenly accelerates, its instantaneous velocity remains constant but its instantaneous speed increases.

Answer;

A.It’s not moving.

Explanation;

Position-Time graphs display the motion of a object by showing the changes of velocity with respect to time.

The motion of a car on a position-time graph that is represented with a horizontal line indicates that the car has stopped moving.

A straight line with a positive slope indicates that the car is moving at a constant velocity, and thus the slope is constant. On the other hand, a curve with a changing slope, shows that the velocity is changing.

Actually it DOES mean that it is not moving. That other guy was right and you gave him 2 stars!

We cannot estimate the blood's acceleration during the speeding up phase without knowing the time taken.

The student wants to estimate the blood's acceleration during the speeding up phase of its motion. To solve this, we can use the equation for acceleration:

a = (v - u) / t

where a is the acceleration, v is the final velocity, u is the initial velocity, and t is the time taken. In this case, the blood is accelerated from rest (0 cm/s) to 30.0 cm/s in a distance of 1.80 cm. To calculate the time (t), we can rearrange the equation to:

t = (v - u) / a

Substituting the values, we have:

t = (30.0 cm/s - 0 cm/s) / a

To find a, we need to know the value of t. Unfortunately, the value of t is not given in the question, so we cannot determine the blood's acceleration during the speeding up phase without knowing the time taken. Therefore, we cannot provide an estimate for the blood's acceleration in this case.

Answer:

less energy would need to be generated.

Explanation:

What is efficiency?

Energy efficiency just means that you need less energy for the same consumption or demand.

In distribution and transportation of energy we lose some of the energy generated at the power plants, be it in the form of heat radiation because of the resistance of power cables or in the form of electromagnetic radiation, so if we improve efficiency, then less energy is lost in those two ways to power the same demand. Putting it simply, let's say your house demands 10kW, and the cable connecting you with the utility loses 1kW, then:

1kW+10kW = 11kW <- That needs to be generated

But if we improve that efficiency by 50% then the loses are cut by half, 1kW/2=0.5kW, so:

0.5kW+10kW = 10.5 kW <- 0.5 kW less that need to be generated. Multiply that by the number of homes in America for example and you have  tremendous power-saving potential