A train whose proper length is 1200 m passes at a high speed through a station whose platform measures 900 m, and the station master observes that when the train passes it occupies exactly the entire length of the platform. What is the speed of the train?

Answers

Answer 1

Answer:

0.66c

Explanation:

Use length contraction equation:

L = L₀ √(1 − (v²/c²))

where L is the contracted length,

L₀ is the length at 0 velocity,

v is the velocity,

and c is the speed of light.

900 = 1200 √(1 − (v²/c²))

3/4 = √(1 − (v²/c²))

9/16 = 1 − (v²/c²)

v²/c² = 7/16

v = ¼√7 c

v ≈ 0.66 c


Related Questions

It a process or act of natural growth.



Answers

The answer is process

Find the speed of the mobile after 4 seconds

Answers

Answer:

27 m/s

Explanation:

V_final = v_initial + a*t

V_final = 15 + 3 * 4

V_final = 27 m/s

A catapult is usedto fire an object into the air describe the energy transfers when the catapult is released and stretched

Answers

Explanation:

potential energy ===> kinetic energy

when an object is stretched there will be a stored energy in it enough to react to the upcoming change

that is the potential energy

similar to a stretched elastic band

kinetic energy is the energy on a moving object

*If a kinetic energy takes place there must gave been a potential energy before*

A catapult is used to fire an object into the air, the potential energy transfers as the elastic potential energy and to the kinetic energy when the catapult is released and stretched.

What is the energy conversion taken place in Catapult?

The potential energy is associated with bodies that are above a reference point, at that reference point the value of potential energy is taken as zero. For example, if an object with a mass M is in a tower that is 140 meters high, its potential energy is defined as the product of the mass of the object by gravity and by the height at which the object is measured from the reference point.

Ep =mgh

When talking about elastic objects such as springs or elastic fibers, it is usually understood that there is an elastic potential energy associated with the constant of the spring. This can be calculated using the following equation:

U ela = 1/2×k×(Dx)²

where:

k = elastic constant of the elastic material [N/m]

Dx = distance stretched or compressed of the elastic material [m]

U = elastic energy [Joules]

So, there are difference between the elastic potential energy and the potential energy.

In a catapult, Initially, energy is stored in the form of potential energy which is later converted into kinetic energy. Potential energy can be stored in the form of elastic potential energy in the case of elastic. It suddenly releases the energy to propel the object into the air.

Learn more about catapult,

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how to find volume of a cuboid in cm3

Answers

Answer:

we have to use formula of volume to find volume of a cuboid. ( i.e v = l ×b ×h)

Explanation:

here, let your length of cuboid be x cm, breadth be y cm and height be z cm .

now, formula to find volume of cuboid = length ×

breadth × height.

so, v( volume)= l (length)× b (breadth)× h (height)

or, v= x cm × y cm × z cm

therefore, volume is xyz cm^3..... answer.

hope it helps..

Answer: length times width times height

Explanation:

Law of conservation
of momentum

Answers

Answer:

Explanation:

Law of conservation of momentum is applied in solving collision problem. When two body collides, their momentum after collision can be determined using the law.

The law States that the sum of momentum of two bodies before collision is equal to the sum of their momentum after collision. Before collision, both bodies moves with a different velocity while during some cases, the bodies moves with a common velocity after collision.

Whether they move with or without the same velocity depends on the type of collision that exists between them after the collision. After collision, some object sticks together and move with a common velocity while some doesn't.

If the bodies sticks together after collision, the type of collision that occur is inelastic (energy is not conserved) and if they splits after collision, the type of collision that occur is an elastic collision (energy is conserved).

Let m1 and m2 be the masses of the bodies

u1 and u2 be their velocities before collision

v1 and v2 be their velocities after collision.

According to the law;

m1u1 + m2u2 = m1v1 + m2v2

Note that momentum = mass × velocity of the body.

On January 22, 1943, in Spearfish, South Dakota, the temperature rose from −4.00°F to 45.0°F over the course of two minutes (the current world record for the fastest recorded temperature change). By how much did the temperature change on the Celsius scale?

Answers

Answer:

The change on the Celsius scale is 27.22 °C.

Explanation:

The conversion of Fahrenheit to Celsius is the following:

[tex]T = \frac{5}{9}(^{\circ} F - 32)[/tex]

So, we need to convert T₁ and T₂ from °F to °C:

[tex]T_{1} = \frac{5}{9}(^{\circ} F - 32) = \frac{5}{9}(- 4 - 32) = -20 ^{\circ} C[/tex]

[tex]T_{2} = \frac{5}{9}(^{\circ} F - 32) = \frac{5}{9}(45 - 32) = 7.22 ^{\circ} C[/tex]

Hence, the change on the Celsius scale is:

[tex] \Delta T = T_{2} - T_{1} = 7.22 - (-20) = 27.22 ^{\circ} C [/tex]

Therefore, the change on the Celsius scale is 27.22 °C.

I hope it helps you!

A scientist is studying the effects of sunlight on rose bushes. Which of the
following is a testable question about this topic?

Answers

Answer:

Does more sunlight make rose bushes grow taller?

Explanation:

When conducting a research, the researcher usually poses research questions in order to confirm or disprove the research hypothesis. A research question addresses the key issues and questions that the research project is intended to answer. Good research questions always aim at improving the body of knowledge on the selected topic of the research. Research questions must be narrowed down to specific details of the topic. They must also be testable, they must not be vague.

If I am studying the effect of sunlight on rose bushes, then the question, 'does more sunlight make rose bushes grow taller?' Is apt to the research because it can be tested by exposing various thorn bush plants to varying degrees of sunlight and recording my observation.

Answer:

If rose bushes receive more hours of sunlight each day, they will grow taller.

Explanation:

I just answered it on Apex, and they like to switch up how they word things sometimes.

Radar uses radio waves of a wavelength of 2.5 m . The time interval for one radiation pulse is 100 times larger than the time of one oscillation; the time between pulses is 10 times larger than the time of one pulse. What is the shortest distance to an object that this radar can detect

Answers

Answer:

The minimum distance to the object that the radar can detect is 124.995 m

Explanation:

Here, we are to calculate the shortest distance to an object the radar in the question can detect.

Mathematically;

v = c/λ

Where v is the frequency, c is the speed of light and λ is the wave length

Thus;

v = (3 * 10^8)/2.5 = 1.2 * 10^8 Hz

Mathematically, the time period

t = 1/v = 1/(1.2 * 10^8) = 0.000000008333 = 8.333 * 10^-9 sec

From the question, we are told that the transmitting time is 100 times a single oscillation

Transmitting time = 100 * one oscillation

Hence Transmitting time = 100 * 8.33 * 10^-9 = 8.33 * 10-7

Mathematically;

Minimum distance =( Transmitting time * speed of light)/2 =

(8.33 * 10^-7 * 3 * 10^8)/2 = 124.995 m

A car travels from city A to city B separated by 282 km and the journey takes approximately 6 hours and 32 minutes. If they come back in 8 hours. What is your average speed throughout the journey? What is its average speed?

Answers

Answer:

38.8 km/hr

Explanation:

The total distance is 2 × 282 km = 564 km.

The total time is 6 hr 32 min + 8 hr = 14 hr 32 min = 14.533 hr.

The average speed is:

(564 km) / (14.533 hr)

38.8 km/hr

Part E Now convert the time from seconds to years. This value is the approximate age of the universe. Write the age in scientific notation. Use the conversion, 1 year = 3.154 × 107 seconds.

Answers

Explanation:

The age of the universe is 13.8 billion years.

We know that,

1 billion years = 10⁹ years

So,

[tex]13.8\ \text{billion years}=13.8\times 10^9\ \text{years}[/tex]

We need to convert the age of the universe to the scientific notation.

Since, [tex]1\ \text{year}=3.154\times 10^7\ s[/tex]

So,

[tex]13.8\times 10^9\ \text{years}=13.8\times 10^9\times 3.154 \times 10^7\\\\=4.35\times 10^{17}\ s[/tex]

So, the age of the universe is [tex]4.35\times 10^{17}\ s[/tex].

Answer:

So the universe is approximately 1.34 x 10^10 years old

Explanation:

Edmentum

A duck is 12 m from the edge of a pond. A student stands in the middle of the pond
and creates ripples that travel past the duck and towards the edge of the pond. The
ripples are produced uniformly at 2 ripples per second. The student determines that
the ripples take 3.0 seconds after they pass the duck to reach the edge of the pond.
Determine the wavelength of the ripples.

Answers

Answer:

The wavelength is 2 meters

Explanation:

The relationship between the frequency, the speed and the wavelength is given by the relation;

v = f × λ

The given parameters are;

The distance of the duck from the edge of the pond = 12 m

The number of ripples produced per second = Frequency, f = 2 Hz

The time it takes the ripple to reach the edge of the pond after travelling past the duck = 3 seconds

Therefore, speed of the wave, v = Distance/time = 12 m/(3 s) = 4 m/s

The wavelength, λ, is therefore;

λ = v/f = (4 m/s)/(2 Hz) = 2 meters.

You are given three pieces of wire that have different shapes (dimensions). You connect each piece of wire separately to a battery. The first piece has a length L and cross-sectional area A. The second is twice as long as the first, but has the same thickness. The third is the same length as the first, but has twice the cross-sectional area. Rank the wires in order of which carries the most current (has the lowest resistance) when connected to batteries with the same voltage difference.
A. Most Current
B. Wire of length L and area 2A
C. Wire of length L and area A
D. Wire of length 2L and area A
E. Least Curren

Answers

Answer:

Explanation:

Resistance of first wire

R₁ = ρL / A where ρ is specific resistance

for second wire the resistance

R₂ = ρ2L / A = 2 ρL / A

For third wire

R₃ = ρL /2 A

The resistance is in the order

R₂ > R₁ > R₃

So , current will be maximum in R₃

I₃ > I₁ > I₂

Where I₁ , I₂  and I₃ is current in first , second and third wire .

analyze this physics mystery and be marked brainliest​

Answers

Answer:

The two middle chains are for suspension of the glass surface, while the fours chains at all corners prevents tilting

Explanation:

From the picture, the the frame bearing the glass surface is suspended by the two metal chains at the middle,

While the balance to avoid tilting to either directions is maintained by the four  chains at all corners.

Indicate the direction of heat flow in each scenario. Scenario A: Scenario B: Scenario C: Scenario D:

Answers

Answer:

Scenario A:  toward object 1

Scenario B: toward object 2

Scenario C:  toward object 1

Scenario D:  toward object 1

Explanation:

The heat transfer will take place for different cases are as follow

A: From skin to lotion

B: From lasagna to plate

C: Lava to ocean water

D: From sidewalk to egg

What is heat transfer?

Heat always flows from a higher temperature body to a low-temperature body. Heat transfer, any or all of several kinds of phenomena, is considered a mechanism, that conveys energy and entropy from one location to another.

The specific mechanisms are usually referred to as convection, thermal radiation, and conduction (see thermal conduction).

Conduction involves the transfer of energy and entropy between adjacent molecules, usually a slow process.

Convection involves the movement of heated fluid, such as air, usually a fairly rapid process.

Radiation refers to the transmission of energy as electromagnetic radiation from its emission at a heated surface to its absorption on another surface, a process requiring no medium to convey the energy

The heat transfer will take place for different cases are as follow

A: From skin to lotion

B: From lasagna to plate

C: Lava to ocean water

D: From sidewalk to egg

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What is the angle of deviation in a plane mirror at normal incidence?​

Answers

Answer:

The deviation of a mirror is equal to twice the angle of incidence.The total angle between the straight-line path and the reflected ray is twice the angle of incidence. This is called the deviation of the light and measures the angle at which the light has strayed from its initial straight-line path.

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Formulating a Hypothesis: Part II
Now you will focus on a second hypothesis. This
hypothesis can be very similar to the first, but this time
you want to focus only on the second variable in
question, speed. What could be a hypothesis that would
illustrate the relationship between speed and kinetic
energy? Use the format of "if.. then... because..." when
writing your hypothesis.
If we have a ball rolling its speed could determine the amount of
kinetic energy in it while in movement

Answers

Explanation:

The kinetic energy of an object is given by :

[tex]E=\dfrac{1}{2}mv^2[/tex]

m is mass of the object

v is the speed of the object

It is clear from the above relation that the kinetic energy of the object is directly proportional to the product of mass and velocity.

The hypothesis can be :

If the speed of the object increased then its kinetic energy increase because kinetic energy is directly proportional to ist speed.

The kinetic energy of an object is given by :

m is mass of the object

v is the speed of the object

It is clear from the above relation that the kinetic energy of the object is directly proportional to the product of mass and velocity.

The hypothesis can be :

If the speed of the object increased then its kinetic energy increase because kinetic energy is directly proportional to its speed.

A body is thrown vertically upwards, remaining 4s in the air. Calculate the maximum height that the body reaches.

Answers

Answer:

20 m

Explanation:

Given:

v = 0 m/s

a = -10 m/s²

t = 4 s / 2 = 2 s

Find: Δy

Δy = vt − ½ at²

Δy = (0 m/s) (2 s) − ½ (-10 m/s²) (2 s)²

Δy = 20 m

2. A solid sphere and a solid cylinder, both uniform and of the same mass and radius, roll without slipping at the same forward speed. It is correct to say that the total kinetic energy of the solid sphere is A) more than the total kinetic energy of the cylinder. B) less than the total kinetic energy of the cylinder. C) equal to the total kinetic energy of the cylinder.

Answers

The correct answer is B) less then the total kinetic energy of the cylinder,
Please mark brainliest

a solid weighs 20gf in air and 18 gf in water.Find the specific gravity of the solid. Please show your work.​

Answers

Answer: It is given that A body weighs 20gf in air and 18. 0gf in water. Hence, the answer X-3 = 7.

If three cars, each of mass 1000 kg , occupy the NE, SE, and SW corners, determine the coordinates of the CM of the loaded ferryboat relative to the center of the raft. Take the origin to be at the CM of the raft.

Answers

Answer:

Using X = sum( x's * mass)/sum( masses)

= [(0)*(6400)+ (-9.5*1000) + (9.5)*(1000) + (9.5)*(1000)]/(6400+1000+1000+1000)

= 1.01 m

Y = sum( y's * mass)/sum( masses)

= [(0)*(6400) + (9.5)*(1000) +(-9.5)*(1000) + (-9.5)*(1000)]/ (6400+1000+1000+1000)

= -1.01 m

identify the motion when a car is moving with constant speed along a curve

Answers

Answer:

Uniform circular motion

Explanation:

When a car is moving with constant speed along a curve, it will said to have uniform circular motion. The speed of the car remains constant in this case. But its velocity keeps on changing. The velocity can be calculated by drawing the tangent on the circle. Hence, the motion of the car is uniform circular motion.

Answer:

Uniform motion

Explanation:

The motion when a car is moving with constant speed along a curve is an example of uniform motion.

A car moving at constant speed covers equal distances in equal intervals of time. The average speed remains the same in uniform motion.

The curve defines the path of the motion and the speed remains constant.

Calculate the speed of a car that travels 355km in 15 hours , a good answer please

Answers

Answer:

23.67 km / hr

Explanation:

car travels 355 km (d)

duration = 15 hrs  (t)

average speed formula = v = d / t

v = 355 km / 15 hr

v = 23.67 km / hr

Explanation:

Hello, there!!!

Here, your question is asking about the speed and the given are:

distance (s)= 355km

time (t) = 15hrs.

speed (v)=?

now,

we have the formula:

v= s/t

or, v = 335km /15 hrs.

Therefore, the speed of car was 23.67km/hr.

Hope it helps..

A small child has a wagon with a mass of 10 kilograms. The child pulls on the wagon with a force of 2 newtons. What is the acceleration of the wagon?

Answers

Explanation:

F = ma

2 N = (10 kg) a

a = 0.2 m/s²

How do you find time with current and charge

Answers

[tex]\mathfrak{\huge{\pink{\underline{\underline{AnSwEr:-}}}}}[/tex]

Actually Welcome to the Concept of the Current Electricity .

Since we know that, Current is Charge per unit time.

so we get as,

Q = I*t

here, Q = charge, I = current, t = time.

Unpolarized light, with an intensity of I0, is incident on an ideal polarizer. A second ideal polarizer is immediately behind the first and its axis of polarization is oriented at an angle of 60° relative to the first polarizer’s. How much of the light will be transmitted through the system?

Answers

Answer:

The light transmitted through the system will be 0.125*I₀.  

Explanation:

The light transmitted through the system can be found using Malus Law:

[tex] I = I_{0}cos^{2}(\theta) [/tex]    (1)

Where:

I: is the intensity of the light transmitted

I₀: is the initial intensity

θ is the angle relative to the first polarizer’s = 60°

Because the light transmitted by the first polarizer is dropped by half, the equation (1) results as:  

[tex] I = \frac{I_{0}}{2}cos^{2}(\theta) [/tex]

[tex] I = \frac{I_{0}}{2}cos^{2}(60) [/tex]

[tex] I = 0.125I_{0} = \frac{1}{8}I_{0} [/tex]

Therefore, the light transmitted through the system will be 0.125*I₀.  

I hope it helps you!

For the electric circuit given below, calculate: 3 (i) the equivalent resistance of the circuit, (ii) the total current drawn from the battery and (iii) the voltage across 7Ω resistor.

Answers

Answer:

1)31/3Ω

2)18/31A

3)4.06V

Explanation:

According to the diagram and 10 Ω resistors are parallel to each other, parallel resistor can be calculated using the formula below

1/R= 1/R1 + 1/R2

But we know R1= 5 Ω and R2= 10 Ω

1/R= 1/5 + 1/10

R= 10/3 Ω

=3.33 Ω

Then if we follow the given figure, 10/3 Ω and 7Ω are now in series then

Req = 10/3 +7

Req= 31/3 Ω

Therefore, equivalent resistance = 31/3 Ω

According to ohms law we know that V= IR

Then I= V/R

Where I= current

R= resistance

V= voltage

I= 6/(31/3)

I= 18/31A

We can now calculate the voltage accross the resistor which is

V=(18/31)× 7

V=4.06V

Therefore, the voltage accross the 7 ohm resistor is 4.06V

CHECK THE FIQURE AT THE ATTACHMENT

when vector contains distance and direction it also known as

Answers

When vector contain distance and direction it is also known as displacement .

Select the correct answer.
According to the Universal Law of Gravitation, every object attracts every other object in the universe. Why can’t you feel the force of attraction between you and Mars?
A.
There is no force of attraction between you and Mars.
B.
Your mass is too low.
C.
Mars is a larger planet than Earth.
D.
Mars is a long distance away.

Answers

Answer:

D. Mars is a long distance away

explain relative velocity.

Answers

Answer:

The relative velocity of an object A with respect to another object B.

Explanation:

The relative velocity of an object A with respect to another object B is the velocity that object A would appear to have to an observer situated on object B moving along with it.

we can catch a rolling ball but not a flying bullet?? give reason

Answers

Answer:

yeah this statement is tru

Explanation:

it is because the speed of the bullet is more than the speed of rolling ball .so from this reason we cannot catch a bullet.

A bullet will be moving much faster than a rolling ball. Even seeing a bullet in flight requires it to be extremely low velocity.

Other Questions
which of the following has the least steep graph? A.) y = 1/2x + 3 B.) y = x + 24C.) y = 3x - 16D.) y = 2x + 7/15 Historically, the proportion of students entering a university who finished in 4 years or less was 63%. To test whether this proportion has decreased, 114 students were examined and 51% had finished in 4 years or less. To determine whether the proportion of students who finish in 4 year or less has statistically significantly decreased (at the 5% level of signficance), what is the critical value Robert withdrew $100,000 from an account that paid 10 percent annual interest and used the funds to purchase real estate. After one year he sold the property for $120,000. The accounting profit on this deal was: Determine whether the value given below is from a discrete or continuous data set. In a test of a method of gender selection, 725 couples used the XSORT method and 368 of them had baby girls. Choose the correct answer below. A. The data set is neither continuous nor discrete. B. A continuous data set because there are infinitely many possible values and those values can be counted C. A continuous data set because there are infinitely many possible values and those values cannot be counted D. A discrete data set because there are a finite number of possible values Let $S = 2010 + 2011 + \cdots + 4018$. Compute the residue of $S$, modulo 2009. in the diagram ,a and 46 are complementary angles. It is given that a and b are supplementary angles and the angle conjugate to c is 283. Calculate the values of a,b,c and d. pleaseeeee answer soonn Q 8.32: The financial statements of the Otter Company report net sales of $800,000 and accounts receivable of $40,000 and $20,000 at the beginning of the year and end of year, respectively. What is the accounts receivable turnover for the Otter Company Which description best describes the solution to the following system of equations? y = 2x + 3 y = x + 6 Find x y, if x = 3 5/6 and y = 3 3/4 .Express your answer in simplest form. What is the equation of the line with a slope of 4 and a y-intercept of -5? Triangle ABC has vertices A(-5, -2), B(7, -5), and C(3, 1). Find the coordinates of the intersection of the three altitudes What is the solution to the following equation?5(2x - 6) + 20 = 10090503O2 Please select the word from the list that best fits the definition Compr un billete aqu. how are most stocks brought and sold? A mostly individual sell their stocks directly to other individuals B most stocks are sold directly to investors by the issuing corporation c the government sells stock directly to the people D most investors purchase stocks through stock market The length of a rectangular field is twice its breadth. If the area of the rectangular field is 98 sq. M., then what is the perimeter of the field? Also find the approximate length of the diagonal of the field. You are considering two independent projects. Project A has an initial cost of $125,000 and cash inflows of $46,000, $79,000, and $51,000 for Years 1 to 3, respectively. Project B costs $135,000 with expected cash inflows for Years 1 to 3 of $50,000, $30,000, and $100,000, respectively. The required return for both projects is 16 percent. Based on IRR, you should: What can he assume about the number of adenine?The number of adenine bases will be equal to the number of guanine bases.The number of adenine bases will be equal to the total of all the other bases.The number of adenine bases will be equal to the number of thymine bases.The number of adenine bases will be half of the number of cytosine bases. Importers Direct arranged to have a French winery ship a large quantity of fine wine to the United States. By signing a(n) ______________, Importers Direct authorized its bank to make full payment to the French winery if and when the wine arrives at the Importers Direct warehouse in Philadelphia. At the beginning of July, Zachary opened a savings account that pays 4% interest on money in the account at the end of the year. How much money does Zachary have at the end of the year if he deposits $150 each month for the rest of the year? a $936 b $70 c $1870 d $2000 a variable with an exponent is a perfect square if the exponent is divisible by____