Frames of Reference Practice Solutions
A girl is on a train that is headed East at 100 miles per hour. The girl is walking at 5 miles per hour
toward the back of the train.
1.
What is the speed and direction of the train if the girls is the frame of reference?

Answers

Answer 1

Answer:

5 mph East.

Explanation:

If the girl is the frame of reference, we need to check the train's relative movement to the girl.

If the girl was not moving inside the train, the speed of the train would be zero, because the train and the girl would be moving together with the same speed and direction.

If the girl is moving 5 mph toward the back of the train, the movement of the train should be calculated considering the girl is fixed (not moving).

So the direction of the train movement would be the inverse of the girls movement (the girl is going West), then the speed and direction of the train is 5 mph and East.


Related Questions

do you believe there is an end to the universe? Explain your answer

Answers

yes. time and space has to stop somewhere we just don’t know enough information yet

A ball is thrown upward with ten units of momentum initially. What is the “recoil” momentum of the earth? Why do we not feel this?

Answers

Answer:

1.) Momentum = 10 units

2.) Because of gravity

Explanation:

According to the Newton 3rd law of motion, we realise that in collision, momentum is always conserved.

So, if a ball is thrown upward with ten units of momentum initially, the “recoil” momentum of the earth will be approximately 10 units of momentum. We do not feel this because of the gravity.

How does a force do negative work on an object

Answers

Answer:

Explanation:  

How does a force do negative work on an object ; This is when the direction of motion is opposite to the direction of the force

To solve this we must be knowing each and every concept related to work. Therefore, a force do negative work on an object,  when the direction of motion is opposite to the direction of the force.

What is work?

A task requiring mentally or physically effort in order to accomplish a goal or outcome is referred to as labor in general. When we lift heavy objects off the ground or push or pull large objects, we are performing labor. When the direction of motion is opposite to the direction of the force, work is negative.

Another word we frequently use is energy. Energy and amount of work performed are typically associated, because a person who's really feeling particularly excited is capable of accomplishing a lot of work.

Therefore, a force do negative work on an object,  when the direction of motion is opposite to the direction of the force.

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When a shot putter exerts a force of 140 N on a 7.5 kg shot, what its is acceleration?

Answers

18.67

Explanation:

acceleration=Force÷mass

acceleration=140÷7.5

acceleration=18.67

Answer:

Explanation:

Force,F = mass,m × acceleration due to gravity,g

⇒g=F/m

⇒g=140/7.5

⇒g=18.67 N/kg

Which statement correctly describes gravity?
O an attractive force that acts between all objects through contact
O an attractive force that acts between all objects without contact
O a repulsive force that acts between all objects through contact
a repulsive force that acts between all objects without contact

Answers

The second one is best.  Gravity is an attractive force that acts between all objects, whether they're in contact or not.

Gravity is an attractive force that acts between all objects, whether they're in contact or not.

What is gravity?

Gravity, also called gravitation, in mechanics, is the universal force of attraction acting between all matter. It is by far the weakest known force in nature and thus plays no role in determining the internal properties of everyday matter.

On the other hand, through its long reach and universal action, it controls the trajectories of bodies in the solar system and elsewhere in the universe and the structures and evolution of stars, galaxies, and the whole cosmos.

On Earth, all bodies have a weight, or downward force of gravity, proportional to their mass, which Earth’s mass exerts on them. Gravity is measured by the acceleration that it gives to freely falling objects. At Earth’s surface, the acceleration of gravity is about 9.8 metres (32 feet) per second per second.

Thus, for every second an object is in free fall, its speed increases by about 9.8 metres per second. At the surface of the Moon, the acceleration of a freely falling body is about 1.6 metres per second per second.

Hence Gravity is an attractive force that acts between all objects, whether they're in contact or not.

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The mass of Mars is 6.42 × 1023 kg. Its moon Phobos is 9378 kilometers away from Mars and has a mass of 1.06 × 1016 kg. What is the gravitational force between Mars and Phobos? 5.16 × 1015 N 5.16 × 1021 N 4.84 × 1022 N 4.84 × 1025 N

Answers

Answer:

A on Edge 5.16 x 10^15 N

Explanation:

The gravitational force between Mars and Phobos is 5.16*10^15 N.

Using the formula

F = G m1 m2/ r^2

  = 6.67*10^-11*6.42*10^23*1.06*10^16/(9378)^2

  = 45.39*10^28/87946884

  = 5.16 * 10^15 N

What is gravitational force ?

"The force of attraction on a body by earth is called gravitational force." Example : The leaves and fruits fall from a tree downwards towards the ground, water in a river flows down streams, a ball thrown up goes to a height and then returns back on ground are some examples of motion due to gravitational force.

What is phobos ?

"Phobos is the larger of Mars' two moons and is 17 x 14 x 11 miles (27 by 22 by 18 kilometers) in diameter. It orbits Mars three times a day, and is so close to the planet's surface that in some locations on Mars it cannot always be seen."

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When a fuse blows
Check all that apply
O A it's a sign that there might be something causing too much
current to flow in the circuit
O B it is best to replace it with a much larger fuse
o you should replace the fuse and check to see what might have
caused it to blow
O the circuit catches fire

Answers

Answer:  A

it's a sign that there might be something causing too much

current to flow in the circuit

Explanation: When a fuse blows, one of the causes may be short circuit. Also, it's a sign that there might be something causing too much

current to flow in the circuit leading to overloading. That is, drawing to much of power that can cause the metal inside the fuse to melt.

Option A is the best answer.

What is nuclear energy?
A. Stored energy due to an object's location or position
O.B. Energy carried by moving electrons
O C. Energy due to an object's motion
O D. Energy released from atoms

Answers

Answer:

the answer from nod energy from atoms

Boats use echo sounders. Pulses of sound waves are reflected by the sea bed and
detected by a sensitive microphone. The time between an echo sounder sending and
receiving a pulse is 0.005 s. The device calculates the depth of the sea, using the speed
of sound in sea water, which is 1500 m/s.
Use this information to calculate the depth of the sea. Show your working.

Answers

Answer: depth = 3.75 m

Explanation:

Taken the speed of the sound in sea to be V = 1500 m/s

The time between an echo sounder sending and receiving a pulse is 0.005 s. That is,

Total time T = 0.005

Formula for echo is:

V = 2X/T

Where X = distance covered

Substitute V and T into the formula

1500 = 2X/0.005

Cross multiply

7.5 = 2X

Make X the subject of formula

X = 7.5/2

X = 3.75 m

Therefore, the depth of the sea is 3.75 m

A planet has a period of revolution about the Sun equal to Tand a mean distance from the Sun equal to R. T varies directly as _____.

A. R
B. R²
C. R3
D. R4
E. R5

Answers

Answer:

C.  R3

Explanation:

Answer:

C.  R3

Explanation:

Plato

Two waves with amplitudes of 52 units and 98 units come together. Their amplitude, which is measured at a specific point and time, is 46 units. What wave behavior explains this value? A. destructive interference B. constructive interference C. refraction D. diffraction E. partial transmission

Answers

Answer: A

destructive interference

Explanation: Interference involves coming together of two waves of the same type. E.g sound waves, water waves e.t.c

Whenever two waves of different amplitude interferes with one another and there is increase in amplitude, this is known as constructive interference.

But whenever there is decrease in amplitude as a result of interference of the two waves, this is known as destructive interference.

If Two waves with amplitudes of 52 units and 98 units come together. Their amplitude, which is measured at a specific point and time, is 46 units. The wave behavior that explains this value is destructive interference because of decrease in the units of amplitude.

Answer:

destructive interference

Explanation: Plato user


A ball is thrown vertically downward with an initial speed of 12.0 m/s from a height of 10.0 m above the ground. Ignoring air resistance, what is the speed of the ball when it reaches the ground?
(A) 18.5 m/s
(B) 14.6 m/s
(C) 14.0 m/s
(D) 12.8 m/s
(E) 12.0 m/s
Can you just take a picture of your work clearly because I have to show work. Thanks.

Answers

Answer:

18.5 m/s

Explanation:

Take down to be positive.

Given:

Δy = 10.0 m

v₀ = 12.0 m/s

a = 9.8 m/s²

Find: v

v² = v₀² + 2aΔy

v² = (12.0 m/s)² + 2 (10 m/s²) (10.0 m)

v = 18.5 m/s

There is a large box and a small box on a table. The same force is applied to both boxes. The large box moves two feet and the small box moves one foot. Which movement shows the most work done? The movement of the large box shows more work because the box moved a longer distance. The work done is equal because the same force was applied to both boxes. The movement of the small box shows more work because the box moved a shorter distance. The work done was equal because both boxes moved in the same direction as the force.

Answers

Answer:

The movement of the large box shows more work because the box moved a longer distance.

Explanation:

Which of these correctly describes what would happen to a system if 100 J of heat energy is added to it?


1. The potential energy of the system will increase and this will increase the attraction between its particles.


2. The strength of the bonds in system will increase and this will decrease the speed of its particles.


3. The kinetic energy of the system will increase and this will increase the speed of its particles.


4. The kinetic energy of the system will decrease and this will decrease the speed of its particles.

Answers

3 is the correct answer

The correct statement to describe that when a 100 J of heat energy is added to the system, then the kinetic energy of the system will increase  and the speed of the particles will also increase. Hence, option 3 is correct.

What is Kinetic energy?

The force that an object has because it is moving is known as kinetic energy in physics. It is defined as the quantity of effort required to accelerate anybody of a specific mass from rest to its specified velocity. The body keeps its kinetic energy after acquiring it during acceleration, barring changes in speed.

When slowing from its current pace to a condition of rest, the body expends the very same amount of energy. Any term in the Lagrangian of a system that has a derivative in regard to time is formally referred to as kinetic energy.

When the energy is added to the system the gap between the particles will increase due to which the velocity of the molecules will increase and with increase in the velocity the kinetic energy will also increase automatically.

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Measurements show that the wavelength of

a sound wave in a certain material is 18.0 cm. The

frequency of the wave is 1900 Hz. What is the speed of

the sound wave?

Answers

Answer:a sound wave in a certain material is 18.0 cm. The

frequency of the wave is 1900 Hz. What is the speed of

Explanation:

Why is it a good idea to explore the health and fitness field in terms of career
options?
O A. There are career opportunities that require a variety of skills and
talents.
O B. It's a growing field.
O c. Many options in this field allow you to help other people through
your job.
D. All of the above.

Answers

D xrxtxtxt t txt yhhgedd Ed ggdfn

Answer: I think the answer is option D.

Consider a situation where the acceleration of an object is always directed perpendicular to its velocity. This means that
(A) the object is increasing speed.
(B) the object is decreasing speed.
(C) the object is not moving.
(D) the object is turning.
(E) this situation would not be physically possible.

Answers

Answer:

this situation would not be physically possible

What other types of energy are present when turning a generator that were not mention in question ? Explain where in the process they are present . ( Types of energy : Heat , light , sound , radiant , chemical

PLEASE HELP!!

Answers

Answer:

When an object is in motion, there is energy associated with that object. Why should that be the case? Moving objects are capable of causing a change, or, put differently, of doing work. For example, think of a wrecking ball. Even a slow-moving wrecking ball can do a lot of damage to another object, such as an empty house. However, a wrecking ball that is not moving does not do any work

(hope it helps :p    )

A car of mass 1000kg is moving at a speed of 20m/s.
It's brought to rest at a distance of 50m. Calculate the net force acting on the car. ​

Answers

Answer:

-4000 N

Explanation:

1. First let's look at what we know.

Mass: 1000 kg

Initial velocity: 20 m/s

Final velocity: 0 m/s

Displacement: 50 m

2. Let's try and apply a Kinematics equation here.

Looking at what information we have, I would say that this is the best equation:

v[tex]f^{2}[/tex]=v[tex]o^{2}[/tex] + 2aΔx

3. Plug in the numbers.

0 = 400 + 2(a)(50)

0 = 400 + 100a

-400 = 100a

a = -4 m/s^2

4. Use ∑F=ma

∑F = (1000)(-4)

∑F = -4000 N

Resistance is a measure of.
a) the energy per unit charge in a circuit
b) how hard it is for electrons to move through the circuit
c) how hard it is for electrons to move through the battery
d) the number of charge carriers in a circuit

Answers

A
A charge moving through an electric circuit would gain electric potential energy in the internal circuit and lose electric potential energy in the external circuit. Charge has the greatest amount of electric potential energy at the - terminal of the battery.

How do you inhibitors work

Answers

Answer:

By binding to enzymes' active sites, inhibitors reduce the compatibility of substrate and enzyme and this leads to the inhibition of Enzyme-Substrate complexes' formation, preventing the catalyzation of reactions and decreasing (at times to zero) the amount of product produced by a reaction.

Explanation:

A man of mass 60kg climbs up a 20m long staircase to the top of building 10m high. What is the work done by him ​

Answers

Answer:

mass=60kg

h=20m

g=10m/s²

here the work done by the body is equal to its potential energy

work done=P.E.

As we know that P.E.=mgh

putting values

P.E.=60kg×20m×10m/s²

P.E.=1200kgm×10m/s²

P.E.=12000Nm

so the work done by the body is 12000Nm

work done by hi
should be 12000Nm i’m pretty sure

explain why the statement “Dropped objects fall toward the ground" is a law and not a theory

Answers

The statement is a law because it accurately describes EVERY observation. No contradiction has ever been observed that would disprove it, or even cast doubt on it.  

(Wellll ... at least, no contradiction that wasn't immediately and easily explainable, like dropping a helium balloon, or a sheet of paper in a high wind.)

The statement is legal because it accurately describes all that is seen. No controversy has ever arisen to disprove it or cause it to doubt.

What is gravity?

The force of gravity is the force that the planet or another body of gravity absorbs. Gravity holds all the planets in orbit around the sun.

What causes gravity?

The greater the size of the two objects and the shorter the distance between them, the stronger the gravitational force. We also know that gravity can work in a complex system with several components.

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Question 2 (2 points)
Practice tests are available online.
True
False
K12

Answers

True usally quizlet teachers get there work from there
the correct answer is true

describe what factors can make it difficult to reintroduce captive animals into their natural habitats.

Answers

Answer:

Captive animals are animals that are maintained by people in an enclosed place not allowing them to be free. There are several factors that make it difficult to reintroduce them to their natural habitats like:

-Captive animals don't learn the necessary skills to survive in their natural habitats like hunting skills.

-They are too used to have contact with people which makes them vulnerable to hunters.

-Sometimes these animals are not able to integrate with a wild population.

-It has been found that some captive animals are more susceptible to diseases.

All the terrestrial planets have..

A. liquid oceans
B. liquid helium
C. rocky surfaces
D. at least one moon

Answers

The answer is D for sure

Question 1(Multiple Choice Worth 2 points)
(01.01 MC)
Once a scientist has made a hypothesis, what would they typically do next?
O Analysis
O Testing
O Research
O Sharing

Answers

Answer:

Testing

Explanation:

Scientific methods are the steps that scientists follow to find an answer to the questions and to find solutions to the problems. There are certain steps which are followed chronologically in the scientific method:

asking questionsmaking observationsforming a hypothesistesting the hypothesisanalyzing the resultsdrawing conclusioncommunicating the results

helpp me pleassee....

Answers

Answer:

The fundamental wavelength of the vibrating string is 1.7 m.

Explanation:

We have,

Velocity of wave on a guitar string is 344 m/s

Length of the guitar string is 85 cm or 0.85 m

It is required to find the fundamental wavelength of the vibrating string. The fundamental frequency on the string is given by :

[tex]f=\dfrac{v}{2l}\\\\f=\dfrac{344}{2\times 0.85}\\\\f=202.35\ Hz[/tex]

Now fundamental wavelength is :

[tex]\lambda=\dfrac{v}{f}\\\\\lambda=\dfrac{344}{202.35}\\\\\lambda=1.7\ m[/tex]

So, the fundamental wavelength of the vibrating string is 1.7 m.

Click on the boxes below to indicate the number of electrons or protons in each labeled position for a zinc atom (z=30, a=65). Please carefully note the specific information requested for the nucleus by the letter designation.

Answers

Answer:

A 35

B 2

C 8

D 18

E 2

Explanation:

The number of electrons in the positions of the Zn atom, A, B, C, D and E are 30, 2, 8, 18 and 2 respectively.

What is meant by electronic configuration ?

The arrangement of electrons within the orbitals of an atom is known as its electronic configuration.

Here,

The atomic number, which is equal to the number of protons in every neutral atom, is made up of a constant number of electrons in each neutral atom.

The atomic number of an atom is represented by the letter Z.

The mass number of an atom is the sum of the number of protons and neutrons, which are together known as the nucleons, within the nucleus. It is represented by the letter A.

The atomic number of Zinc is given,

Z = 30

From the figure, the electronic configuration can be represented as,

A = 30

which is the total number of electrons in Zn atom.

B = 2

which is the innermost orbital.

C = 8

D = 18

E = 2

Hence,

The number of electrons in the positions of the Zn atom, A, B, C, D and E are 30, 2, 8, 18 and 2 respectively.

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What is special relativity

Answers

Answer:

In physics, special relativity (also known as the special theory of relativity) is the generally accepted and experimentally confirmed physical theory regarding the relationship between space and time.

We need special relativity in order to solve for quantum gravity. ... The earth was expanding (thus, it's mass was expanding) through space in all directions in order to create gravity **OOPS** forgot, specifically at an accelerating rate… OR… The space must be pushing toward or down on the earth, from every direction.

Answer:

The theory of special relativity explains how space and time are linked for objects that are moving at a consistent speed in a straight line. ... The theory of special relativity was developed by Albert Einstein in 1905, and it forms part of the basis of modern physics.

Explanation:

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