An train car of total mass of 13000 kg is pulling into a station and slowing down with an acceleration of -4.56 m/s^2. Before the train pulls into the station, a group of 7 stowaway jump off the train. Each stowaway has a mass of 66 kg. If the braking force on the train remains the same, what will be the acceleration of the train once the stowaways jump out of the train?

Answer:

C.490N

Explanation:

Final answer:

In the U.S., a more appropriate distance for business conversations is maintaining an arm's length of space between each other when talking face to face.

Explanation:

In the U.S., a more appropriate distance for business conversations is maintaining an arm's length of space between each other when talking face to face. This means standing approximately 3-4 feet away from the person you are conversing with.

Standing 2 feet away from coworkers may be considered too close and can make them uncomfortable. It's important to pay attention to cues from coworkers, and if they seem uncomfortable, it's best to adjust your distance accordingly. Remember that personal space preferences can vary among individuals, but generally, maintaining an arm's length of space is a good guideline to follow in the U.S.

Work = (force) x (distance)

Work = (21 Newtons) x (9 meters) = 189 Joules

Power = (work done) / (time to do the work)

Power = (189 Joules) / (3 sec)

Power = (63 watts/sec)

Power = 63 watts  (D)

(a) Tangential acceleration: [tex]9.5 m/s^2[/tex]

The tangential acceleration is given by:

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

where

v = 23 m/s is the final velocity of the car

u = 4 m/s is the initial velocity of the car

t = 2 s is the time taken for the car to accelerate from u to v

Substituting the numbers into the formula, we find

[tex]a_t = \frac{23 m/s-4 m/s}{2 s}=9.5 m/s^2[/tex]

(b) Radial acceleration: [tex]0.49 m/s^2[/tex]

The radial acceleration is equivalent to the centripetal acceleration, which is given by:

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

where

v = 16 m/s is the tangential speed

r = 527 m is the radius of the circular orbit

Substituting numbers, we find

[tex]a_r = \frac{(16 m/s)^2}{527 m}=0.49 m/s^2[/tex]

dens = mass/volume. after crushing, vol less so density more. the actual density of the metal is the same, density of can changes

The density of a metal can, whether it is crushed or not, remains the same because density is an intrinsic property of matter, dependent only on the mass and volume of the substance. Changing the can's shape alters its volume but does not affect its mass or its density.

The density of a substance is the ratio of its mass to its volume (Density = Mass / Volume). This physical property is intrinsic to the substance, meaning it doesn't change regardless of the quantity or form the material is in.

When you crush a metal can, you're changing its shape and thereby altering its volume. However, the mass remains the same because you haven't removed or added any material. As a result, the density of the metal in the crushed can stays the same as the metal's density before the can was crushed.

Let's consider a practical example: a block of brass and a piece of rebar. Both have the same mass and are made of the same metal, but the block of brass has a larger volume. Nevertheless, the densities of these substances remain constant. That's because density is an intrinsic property, reflecting the compactness of material in a substance. Hence, even though you change the can's shape (thus, its volume), you have no impact on the metal's density.

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A) increase, warm... would correct.

The kinetic molecular theory says that as water molecules absorb energy, their motion and temperature INCREASE and the sample becomes WARM (Option A).

The kinetic molecular theory is a thermodynamic classical model used to explain the behavior of gases.

In conclusion, the kinetic molecular theory says that as water molecules absorb energy, their motion and temperature INCREASE and the sample becomes WARM (Option A).

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Answer:

The answer is A, a solar eclipse.

Explanation:

Electrons are transferred from one atom to another describes ionic bonding.

Option D

Explanation:

Ionic bonding requires at least one acceptor and one donor. ''Ionic bond'' is the movement of ''valence electrons'' between atoms. It gives two oppositely charged ions after taking place. The metal loses electrons and form a positive cation, and non metals gains electrons to become negative cations. Thus electron donor is a metal, and electron acceptor is usually a non metal. Thus, it is evident that in ionic bonding electrons are transferred between atoms.

Answer:  True

The statement " the synthesis of a large collection of  information that encompasses well tested and verified hypothesis about certain aspects of natural world is known as "scientific theory".    

It was proposed by Charles Darwin and Alfred Russel in the mid 19th century.  

Typically, it is about the relationship between various facts and is a way of providing a concise explanation for what's been observed. A scientific theory is a well- substantiated explanation of an aspect of the natural world.

m = mass of the weight suspended = 1 kg

x₀= stretch in the spring at equilibrium = ?

k = spring constant of the spring = 50.0 N/m

using equilibrium of force ,

spring force on the weight = force of gravity on the weight

k x₀ = mg

50 x₀ = (1 x 9.8)

x₀ = 0.196 m

x = distance by which the weight is pulled below equilibrium = 0.50 m

a = acceleration of the weight

F = spring force on the weight in upward direction ,

force equation for the motion of weight is given as

F - mg = ma

k (x + x₀) - mg = ma

(50)(0.50 + 0.196) - (1) (9.8) = 1 a

a = 25 m/s²

KE depends on velocity. It is easier to answer this question in terms of the earth.

The closer the object (earth/comet) is to the sun, the faster it moves. that means that the fastest moving point would be as the comet/earth passes through point C.

The slowest speed would be the furthest away from the sun which is point A.

Answer: The faster the planet moves the greater the Kinetic Energy.

The Slower the planet moves, the less the KE.

Point A is where it is slowest with the lowest amount of energy.

Discussion

The formula for KE is KE = 1/2mv^2. The mass of the comet or earth is a constant. It doesn't change no matter which point the comet passes through. If v goes down KE will go down. If v goes up, KE goes up.

You posted the same picture yesterday, and learned that ‘C’ is the point of the MOST kinetic energy because it’s closest to the sun and moving fastest. Then I suggested that you review Kepler’s 2nd law.

From that answer OR from Kepler, it should be clear that the LEAST kinetic energy is at ‘A’ .

the answer is C because 10^-3=1/1000 times 2.5=0.0025

The number that represents the standard form given, 2.5x10⁻³, is 0.0025. That is 0.0025 the same as 2.5x10⁻³. Option C is correct.

Standard form can refer to different concepts depending on the context.

Standard Form of a Number:

In mathematics, the standard form of a number refers to a specific way of representing a number using digits and place value. In standard form, also known as scientific notation, a number is expressed as a product of a coefficient (a decimal number greater than or equal to 1 and less than 10) and a power of 10.

For example:

- The number 3,450,000 in standard form is written as 3.45 × 10^6.

- The number 0.0000625 in standard form is written as 6.25 × 10^-5.

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The correct answer is A.

Quizlet is always my trusty sidekick!

I hope this helps!

Cheers, July.

The tendency of a moving object to continue moving in a straight line or a stationary object to remain in place is called inertia.

According to law of inertia, an object maintains its state of rest or motion unless acted upon by an external force. an object can not move on its own unless force is applied on it to move it. also an object can not come to stop on its own unless acted upon by an external force to stop it.This is also known as newton's first law.

There are exactly three ways to move heat from one place to another:

-- conduction

-- convection

-- radiation

Answer:

US Fish and Wildlife Service

Explanation:

There are different federal agencies in the United States of America such as US Forest Service, US Fish and Wildlife Service, Bureau of Land Management and National Park Service. The US Forest Service is the agency that conducts the management of land and other agricultural related services. The Bureau of Land Management is involved with the administration of public lands in the United States. The National Park Service generally conducts the management of all the national parks in the United States. Therefore, the agency that ensures that federal wildlife laws are strictly adhere to is the US Fish and Wildlife Service.

A. Decrease the rate of electrical flow

more resistance = lkess current

Given that,

Initial velocity , Vi = 0

Final velocity , Vf = 40 m/s

Acceleration due to gravity , a = 9.81 m/s²

Distance can be calculated as,

2as = Vf² - Vi²

2 * 9.81 *s = 40² - 0²

s = 81.55 m

For half height, that is, s = 40.77m

Vf= ??

2as = Vf² - Vi²

2 * 9.81 * 40.77 = Vf² - 0²

Vf² = 800

Vf = 28.28 m/s

Therefore, speed of roller coaster when height is half of its starting point will be 28 m/s.  

It is an insulator because it doesn't conduct electricty.

Answer: Option (B) is the correct answer.

Explanation:

A conductor is defined as a substance that allows flow of electrons through it due to which there will be flow of electric current.

Whereas an insulator is defined as a substance through which there will be very less or no flow of electrons. As a result, there will be no flow of electric current through it.

Also, when a material is covalently bonded then it means sharing of electrons has taken place between its atoms. And, covalent materials do not allow flow of electric current through it because of no presence of free electrons or ions.

Thus, we can conclude that the statement it is an insulator best describes a covalently bonded material.

Answer:

It takes more force to stop the 4kg ball rolling at 1m/s.

Explanation:

To stop a ball rolling at 0.2 m/s in 10 seconds means the uniform deceleration needs to be (0.2/10) m/s/s = 0.02 m/s^2. To achieve that on a mass of 8kg requires a (force) = (mass) x (acceleration) = (8kg) x (-0.02 m/s^2) = -0.16 N (negative because it is an opposing force).

To stop a 4kg ball rolling at 1 m/s along the same path as above (implying in 10 seconds of uniform deceleration), will take a deceleration of (1/10 m/s^2) and a (force) = (4kg) x (-0.1 m/s^2) = -0.4 N.

It takes more force to stop the 4kg ball rolling at 1m/s.

(For your interest: you could decide this question also by calculating which ball has the larger kinetic energy and argue that, consequently, to stop that ball a larger force is needed. Kinetic energy is proportional to the square of force exerted)

Answer:

[tex]48 \Omega[/tex]

Explanation:

The resistance of the resistor can be calculated by using Ohm's law:

[tex]V=RI[/tex]

where

V is potential difference across the resistor

I is the current through the resistor

R is the resistance

In this problem, we have

[tex]V=12 V[/tex]

[tex]I=0.25 A[/tex]

So we can re-arrange Ohm's law to calculate the value of the resistance of the resistor:

[tex]R=\frac{V}{I}=\frac{12 V}{0.25 A}=48 \Omega[/tex]

Photons of different kinds of light carry different amounts of energy

einstein's photoelectric equation (and nobel prize citation)

Answer:

Photons of different kinds of light carry different amounts of energy.

Explanation:

As per Einstein's Theory of photoelectric effect we know that

[tex]h\nu = \phi + KE[/tex]

here we know that

[tex]\phi [/tex]= work function of the metal

KE = kinetic energy of ejected electron

[tex]\nu[/tex] = frequency of incident photon.

Now we know that photons of different frequency will have different amount of energy due to which the electrons get ejected out of the surface.

So if the photons have small energy or lesser energy then in that case the electron cannot ejected out

So threshold frequency is the minimum frequency at which electrons ejected out.

Answer:

If it is eight meters per second, and the total distance he has to travel is four hundred meters to complete the race, you divide the total length needed to travel by the average speed per second to see the amount of seconds required to complete the race at that speed.8 meters per second: Speed of runner400 meters: Total distance400/8=50.50 seconds to complete the race at the eight of 8m/s.

The answer would be atoms

Answer: The correct answer is Atom.

Explanation:

Atom consists of proton, electron, neutron and nucleus. The subatomic particles of the atom are electron, proton and neutron.

The electrons revolve around the nucleus while neutrons and protons are located in nucleus. The whole mass of the atom is supposed to be concentrated at nucleus.

The electron is negatively charged particle. The proton is positively charged particle. The neutron has no charge. It is neutral.

Therefore, the correct option is B.

(1) Answer:

6 Newtons

Explanation:

The net force is (mass) x (acceleration) = (3 kg) x (2.0 m/s^2) = 6 N

(2) Answer:

-98 Newtons

Explanation:

Weight (force due to gravity) is (mass) x (gravitational acceleration) = (10 kg) x (- 9.8 m/s^2) = -98 N

The negative sign due to negative acceleration indicates the gravitational force pointing in the negative direction within the defined coordinate system.

Considering the equation for gravitational potential energy, PE=mgh, where m as mass, g as the acceleration due to gravity, and h has the height.

Substituting the numbers given, you’ll get (taking g as 9.81)

PE = 5 x 9.81 x 10

PE = 490.5 J

Therefore the gravitational potential energy will be 490.5 J

The gravitational potential energy of a 5kg object at a height of 10 meters is 490 Joules.

The gravitational potential energy of an object can be calculated using the formula U = mgh, where U is the gravitational potential energy, m is the mass of the object, g is the acceleration due to gravity, and h is the height of the object. In this case, we have a 5kg object at a height of 10 meters. Plugging the values into the formula, we get:

U = (5kg) * (9.8m/s^2) * (10m) = 490 J

Therefore, the 5kg object has 490 Joules of gravitational potential energy when it is 10 meters off the ground.

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T = half life period of decay for atoms of element A = 20,000 years

N₀ = initial number of atoms of element A = 10,000 atoms

N = final number of atoms after time "t" = 2500 atoms

t = time of decay = ?

λ = decay constant = ?

decay constant is given as

λ = 0.693/T

λ = 0.693/20,000

λ = 0.00003465 years⁻¹

atoms after decay for time "t" is given as

N = N₀ [tex]e^{-\lambda t}[/tex]

inserting the values

2500 = (10000) [tex]e^{-(0.00003465) t}[/tex]

t = 40,000 years

so correct choice is

B) 40,000 years

Answer:

B) 40,000 years

Explanation:

You would have only 2500 of A left after 40,000 years. This represents 2 half-lives. After 20,000, ther would be 5,000 of A left and after another 20,000, it would be reduced to 2,500.