Which two statements are true about a system?

a)A system is a group of objects analyzed as one unit.
b)Energy that moves across system boundaries is conserved.
c)There’s only one way to define the boundaries of a system.
d)All systems are made by humans.

Answers

Answer 1
A and c

Because it defines the boundaries of the system

Related Questions

A certain superconducting magnet in the form of a solenoid of length 0.28 m can generate a magnetic field of 7.0 T in its core when its coils carry a current of 80 A. The windings, made of a niobium-titanium alloy, must be cooled to 4.2 K. Find the number of turns in the solenoid.

Answers

Answer:

The number of turns in the solenoid is 19506.

Explanation:

Length of solenoid, L = 0.28 m

Magnetic field, B = 7 T

Current, I = 80 A

Let the number of turns is N.

The formula used to find the magnetic field is

[tex]B = \frac{\mu 0N I}{L}\\\\7 = \frac{4 \times 3.14\times 10^{-7}\times N\times 80}{0.28}\\\\N = 19506[/tex]

What did Ernest Rutherford's experiment of a beam of alpha particles aimed
at a sheet of gold foil lead him to conclude?
A. The theory that atoms were the building block of all matter was
correct.
B. The majority of the atom's mass and its positive charge are
concentrated in the atom's center.
C. An electron has a larger mass than the alpha particles, causing
them to reflect upon collision.
D. J.J. Thomson's theory of electrons suspended in a sea of
positively charged particles was correct.

Answers

Answer:

B - Only a concentration of mass in the nucleus could explain the deflection of the incident particles.

What is an effect of continental drift?

Answers

Answer:  An effect of continental drift is causing tectonic plates resting upon the convecting mantle to move which results in natural disasters like earthquakes, volcanic eruptions, and more.

Define electric current and drift velocity.

Answers

Answer:

Current- the flow of free charges, such as electrons and ions

Drift velocity- the average speed at which these charges move

Answer:

An electric current is the stream of changed particals, such as electrons & ions, moving through an electrical conductor.

The average velocity attained bycharged partical ,such as electrons,in a material due to electric fields

Resistivity of metallic wire
depends on
*
It's length

It's shape
It's thickness
Nature of material​

Answers

Answer:

nature of material

hope this help you

giving me the points are enough

Answers

Answer:

the product of mass and velocity

....in my syllabus

A toy car with a mass of 5.5 kg is moving horizontally over flat ground at a speed of 2.1 m/s. An unknown force then directly pushes the car for a distance of 3 meters, after which the car has a speed of 7.3 m/s. You may assume that air resistance and friction are both negligible. What was the magnitude of the unknown force

Answers

Answer:

The magnitude of the unknown force is 44.8 N.

Explanation:

The force can be found with Newton's second law:                

[tex] F = ma [/tex]

Where:

m: is the mass of the toy car = 5.5 kg

a: is the acceleration

F: is the force =?

We can calculate the acceleration with the following kinematic equation:

[tex] v_{f}^{2} = v_{0}^{2} + 2ad [/tex]

Where:

[tex] v_{f} [/tex]: is the final speed = 7.3 m/s

[tex] v_{0} [/tex]: is the initial speed = 2.1 m/s

d: is the distance traveled = 3 m

Hence, the acceleration is:

[tex] a = \frac{v_{f}^{2} - v_{0}^{2}}{2d} = \frac{(7.3 m/s)^{2} - (2.1 m/s)^{2}}{2*3 m} = 8.15 m/s^{2} [/tex]

Finally, the magnitude of the force is:

[tex]F = ma = 5.5 kg*8.15 m/s^{2} = 44.8 N[/tex]                                  

Therefore, the magnitude of the unknown force is 44.8 N.

I hope it helps you!                                

How does the comets energy change as it moves from point a to point d

Answers

Answer:

At point A, the comet has the least kinetic energy because the comet is resting. 3. From point B to point D its orbit's potential energy is decreasing and its kinetic energy is increasing meaning it's moving more and more

An airplane starts from rest and undergoes a uniform acceleration of 10.8 m/s^2 for 16.7 s seconds before leaving the ground. What is its displacement?

Answers

Answer:

3012.012m

Explanation:

s=it +1/2(10.8)(16.7)^2

Câu 1. Con lắc lò xo treo thẳng đứng, dao động điều hòa với biên độ 2cm và tần số góc 20 rad/s. Chiều dài tự nhiên của lò xo là 30cm. Chiều dài nhỏ nhất và lớn nhất của lò xo trong quá trình dao động là bao nhiêu? Lấy g = 10m/s2.

Answers

Answer:

28 cm and 32 cm

Explanation:

1. The spring pendulum hangs vertically, oscillates harmonic with amplitude 2cm and angular frequency 20 rad/s. The natural length of

a spring is 30cm. What is the minimum and maximum length of the spring during the oscillation? Take g = 10m/s2.

As the amplitude is 2 cm and the natural length is 30 cm. So, it oscillates between 30 -2 = 28 cm to 30 + 2 = 32 cm.

So, the minimum length is 28 cm and the maximum length is 32 cm.

A person climbs out of swimming pool and stands in the open air.Explain why evaporation of water from the surface of the persons body causes the person to feel cold

Answers

Answer:

The person feels cool at first because the swimming pool water is usually cool and he/she has that water on his body. But when it evaporates, the cool air directly touches his body and that's why he/she feels cold.

Thank You! Please mark me Brainliest!

If a roller coaster train has a potential energy of 1,500 J and a kinetic energy of 500 J as it starts to travel downhill, what is its total energy

Answers

Its total mechanical energy is 2,000 J.

We don't have enough information to say anything about its heat energy, its chemical energy, or the energy due to any electrical charge it may be carrying or any magnetic field it may have.

: Chuyển động Một vật xuất phát từ A chuyển động đều về B cách A 240 m với vận tốc 10 m/s. Cùng lúc đó, một vật khác chuyển động đều từ B về A. Sau 15 s hai vật gặp nhau. Tìm vận tốc của vật thứ hai và vị trí hai vật gặp nhau. ​

Answers

mân, whát thē hęll böį

the force between the earth and the body which is at a distance r from the center of the earth is F. What must be this distance for the force to be doubled.

Answers

Answer:

Explanation:

The gravitational force between the earth and another body is F = -GM_em/r^2 r where G = 6.67 times 10^-11 Nm^2/kg^2 is the gravitational constant, M_e = 5.97 times 10^24 kg is the mass of the earth, m is the mass of the other body, and r is the position vector of the second body with respect to the centre of the earth.

Unos amigos de 5 integrantes salen a comer, el primero pide un pollo a la brasa que cuesta S/50.00, el segundo un aeropuerto que cuesta S/28. 50, el tercero se pide una pizza que cuesta S/20,50, el cuarto se pide un tallarín saltado que cuesta a S/10,80 y el quinto un arroz con marisco que cuesta a S/22.00. Uno de ellos paga con tarjeta de crédito de todos ellos, al pagar le incluyen el 5% del uso de tarjeta. ¿Cuánto pagó en total?

Answers

Respuesta:

$138.39

Explicación:

Paso 1: Calcular el total que gastaron

El total que gastaron es igual a la suma de los que gastó cada uno.

$50.00 + $28.50 + $20.50 + $10.80 + $22.00 = $131.80

Paso 2: Calcular el 5% de $131.80

$131.80 × 5% = $6.59

Paso 3: Calcular el total que pagó con la tarjeta

A los $131.80 que gastaron debe sumarle los $6.59 por el uso de tarjeta.

$131.80 + $6.59 = $138.39

Phương trình chuyển động thẳng đều của một chất điểm có dạng: x = 2t – 10. (x: km, t: h). Quãng đường đi được của chất điểm sau 2h là bao nhiêu?

Answers

Answer:

Distance cover in 2  hour = 6 kilometer

Explanation:

Given equation:

x = 2t - 10

where

x = kilometer

t = hour

Find:

Distance cover in 2  hour

Computation:

T = 2

So,

x = 2t - 10

x = 2(2) - 10

x = 4 - 10

x = -6

Distance cover in 2  hour = 6 kilometer

Answer:

The distance is 6 km.

Explanation:

The equation of uniform linear motion of a particle has the form: x = 2t – 10. (x: km, t: h). What is the distance traveled by the particle after 2 hours?

x = 2t - 10

distance traveled after t = 2 hours

Substitute t = 2 in the given expression

x = 2 x 2 - 10

x = 4 - 10

x = - 6 km

So, the distance is 6 km.

The heat required to raise 3 kg of copper from 0°C to 10°C raises 1kg of lead from 10°C to 100°C. If the specific heat capacity of copper is 0.095 cal/g°C,find the specific heat capacity of lead.​

Answers

The specific heat capacity of lead has been determined to be 0.032 cal/g°C.

The specific heat capacity of a substance is the amount of heat required to increase the temperature of its unit mass by 1 Kelvin rise in temperature.  There is no phase change during the process. This can be expressed as:

Q = mcT

c = [tex]\frac{Q}{mT}[/tex]

Where c is the specific heat capacity of the substance, Q is the quantity of heat required, m is the mass of the substance and T is its change in temperature.

In the given question, the heat emitted by the copper mass would be absorbed by the lead mass.

So that;

heat emitted by copper = heat absorbed by lead

[tex]m_{c}[/tex] [tex]c_{c}[/tex]([tex]T_{2}[/tex] - [tex]T_{1}[/tex]) = [tex]m_{l}[/tex][tex]c_{l}[/tex]([tex]T_{2}[/tex] - [tex]T_{1}[/tex])

With the given information in the question, the above equation is expressed as:

3 * 0.095 * (10 - 0) = 1 * [tex]c_{l}[/tex]* (100 - 10)

3*0.095*10 = [tex]c_{l}[/tex] * 90

2.85 = [tex]c_{l}[/tex]*90

[tex]c_{l}[/tex] = [tex]\frac{2.85}{90}[/tex]

  = 0.031667

[tex]c_{l}[/tex] = 0.032 cal/g°C

Therefore, the specific heat capacity of lead is 0.032 cal/g°C.

For more clarifications, visit: https://brainly.com/question/22991121

Many people believe that if the human race continues to use energy as we are now, without change, we'll witness a significant worldwide environmental impact in this century. Research this topic and discuss this possibility. Include concrete examples of specific environmental consequences of global warming.

Answers

Answer:

It is correct to say that if the human race continues to use energy as it is now, without change, we will witness negative environmental impacts around the world in this century.

As a concrete example, we can cite the means of transport that use fossil fuels, such as cars and buses, which release polluting gases into the atmospheric layer and cause the greenhouse effect, contributing to global warming.

To solve these problems, it is necessary to raise the awareness of individuals, so that there is more and more interest and search for environmentally responsible solutions, such as the large-scale production of electric cars, which do not pollute the environment.

Group elements number 11 to 20 as either metallic, non metallic or metalloid.​

Answers

Answer:

The elements are grouped into the different substances by color. As you can see, Lithium, Beryllium, Sodium, Magnesium, Aluminum, Potassium, and Calcium are metals out of the first 20 elements.

Hydrogen, Helium, Carbon, Nitrogen, Oxygen, Fluorine, Neon, Phosphorus, Sulfur, Chlorine, and Argon, are non-metals within the first 20 elements.

Boron and Silicon count as Metalloids in the Periodic Table (properties of both metals and non-metals)

reference- socatric q and a

Explanation:

Answer:

(11-13) - Metals

(14) - Metalloid

(15-18) - Non- metals

(19-20) - Metals

Explanation:

The elements from 11 to 13 are metals. They are Sodium(Na), Magnesium(Mg) and Aluminum(Al) respectively.

The element 14 is a metalloid. It’s Silicon(Si).

The elements from 15 to 18 are non metals. The 18th element is a noble gas known as Argon(Ar).

The elements from 15 to 17 are Phosphorus(P), Sulphur(S) and Chlorine(Cl).

The elements from 19 to 20 are metals. They are Potassium(K) and Calcium(Ca).

Question 6 (5 points)
Which of the following scenarios describes a condition in which resonance can
occur?
A) Tivo tuning forks are struck simultaneously, one with a frequency of 659Hz
and one with a frequency of 639 Hz, causing beats.
B Two tuning forks that vibrate at the same frequency are near each other. One
tuning fork is struck with a mallet so that it vibrates.
C) A tuning fork is over a column of air that is 9/2 the wavelength of the wave
produced by the tuning fork.
An isolated tuning fork is struck with a mallet, causing it to vibrate strongly at
659 Hz.

Answers

Answer:

B. Two tuning forks that vibrate at the same frequency are near each other. One tuning fork is struck with a mallet so that it vibrates.

Explanation:

A wave can be defined as a disturbance in a medium that progressively transports energy from a source location to another location without the transportation of matter.

In Science, there are two (2) types of wave and these include;

I. Electromagnetic waves: it doesn't require a medium for its propagation and as such can travel through an empty space or vacuum. An example of an electromagnetic wave is light.

II. Mechanical waves: it requires a medium for its propagation and as such can't travel through an empty space or vacuum. An example of a mechanical wave is sound.

An amplitude can be defined as a waveform that's measured from the center line (its origin or equilibrium position) to the bottom of a trough or top of a crest.

Resonance can be defined as a phenomenon in which an object is forced to vibrate as a result of the vibration of a second object at the same natural frequency of the first object. Thus, it's an increase in the amplitude of oscillation that occurs when the frequency of a periodically applied force is equal to the natural frequency of the system on which it's acting.

Hence, the scenario that best describe a condition in which resonance can occur is two tuning forks that vibrate at the same frequency are near each other. One tuning fork is struck with a mallet so that it vibrates.

Answer:

B Two tuning forks that vibrate at the same frequency are near each other. One

tuning fork is struck with a mallet so that it vibrates.

Explanation: hope this helps ;)

How does the electric field intensity vary with the increase of distance of the point from the centre of a charged conducting sphere? Explain with graph.​

Answers

Answer:

(i)  Electric field outside the shell:

For point r>R; draw a spherical gaussian surface of radius r.

Using gauss law, ∮E.ds=q0qend

Since E is perpendicular to gaussian surface, angle betwee E is 0.

Also E being constant, can be taken out of integral.

So, E(4πr2)=q0q

So, E=4πε01r2q

How long can a tow rope or chain be?
1. 20 feet 2. 15 feet
3. 5 feet
4. 10 feet

Answers

Answer:

"For towing, a tow chain should be of a length that keeps both vehicles within the maximum 4.5 meter distance, also  tow chains an be any length 20 foot chains are often chosen"  

Explanation:

-  https://letstowthat.com

Also Quick note the feet of tow rope or chain varies on the situation but most longest or 20 feet.  

A motorcycle starts from rest and gains a velocity of 40m/s in 8 seconds. Find (i) acceleration and (ii) distance travelled by the motorcycle.​

Answers

Answer:

• Initial velocity (u) = 0 m/s

• Final velocity (v) = 40 m/s

• time (t) = 8s

Acceleration :

[tex]\implies \sf a = \dfrac{\Delta v}{ t} \\ [/tex]

[tex]\implies \sf a = \dfrac{v - u}{ t} [/tex]

[tex]\implies \sf a = \dfrac{40 - 0}{ 8} [/tex]

[tex]\implies \sf a = \dfrac{40}{ 8} [/tex]

[tex]\implies \bf a = 5 \: {ms}^{ - 2} [/tex]

• Distance travelled by the motorcycle:

[tex] \longrightarrow \sf {v}^{2} - {u}^{2} = 2as \\ [/tex]

[tex]\longrightarrow \sf {(40)}^{2} - {(0)}^{2} = 2 \times5 \times s \\ [/tex]

[tex] \longrightarrow \sf 1600 = 10s[/tex]

[tex]\longrightarrow \sf s = \dfrac{1600}{10} [/tex]

[tex]\longrightarrow \bf s = 160 \: m[/tex]

a motorcycle covers 500 meters in 25 seconds. calculate the average velocity​

Answers

Vtb xe máy là:

v=s : t= 500 : 25=20(m/s)

10. Match the following varibles to their relationship in Newton's 2nd Law. Questions 1. Force and Acceleration 2. Mass and Acceleration 3. Speed and Distance Answer Choices A. Direct Relationship B. Inverse Relationship C. Not in Newton's 2nd Law​

Answers

Explanation:

based on the above information

1.A

2.B

3. C

state Pascal's principle of pressure . please help due tomorrow​

Answers

Answer:

Pascal's law says that pressure applied to an enclosed fluid will be transmitted without a change in magnitude to every point of the fluid and to the walls of the container.

Explanation:

The pressure at any point in the fluid is equal in all directions.

Explanation:

According to pascal law ,Force applied on bulk of water in a container will be distributed to all molecules of water...

the value of 1.0004 to the power 1 by 2 using Binomial approximation is​

Answers

Given:

The given value is [tex](1.0004)^{\frac{1}{2}}[/tex].

To find:

The value of the given expression by using the Binomial approximation.

Explanation:

We have,

[tex](1.0004)^{\frac{1}{2}}[/tex]

It can be written as:

[tex](1.0004)^{\frac{1}{2}}=(1+0.0004)^{\frac{1}{2}}[/tex]

[tex](1.0004)^{\frac{1}{2}}=1+\dfrac{1}{2}\times 0.0004[/tex]      [tex][\because (1+x)^n=1+nx][/tex]

[tex](1.0004)^{\frac{1}{2}}=1+0.0002[/tex]

[tex](1.0004)^{\frac{1}{2}}=1.0002[/tex]

Therefore, the approximate value of the given expression is 1.0002.

How is the potential difference same in capacitors arranged in parallel combination?​

Answers

Answer:

Potential difference across capacitors in parallel

Two or more capacitors are said to be connected in parallel if each one of them is connected across the same two points. In a parallel combination of capacitors potential difference across each capacitor is same but each capacitor will store different charge.

The hair dryer has a plastic case so there is no need for an earth wire connection in the plug ,explain why the hair dryer is still safe to use.

Answers

Answer:

plastics are unable to conduct electricity and heat due to there being no free flowing electrons, meaning they are safe to use.

Explanation:

A car generator turns at 400 rpm (revolutions per minute) when the engine is idling. It has a rectangular coil with 300 turns of dimensions 5.00 cm by 6.46 cm that rotates in an adjustable magnetic field. What is the field strength needed to produce a 24.0 V peak emf

Answers

Answer:

The field strength needed to produce a 24.0 V peak emf is 0.5913 T

Explanation:

From the formula for maximum emf of a generator,

[tex]emf_{max}= NAB\omega[/tex]

∴ [tex]B = \frac{emf_{max} }{NA\omega}[/tex]

Where N is the number of loops

A is cross section of loops

B is magnetic field strength

ω is the angular frequency of loops

From the question, [tex]emf_{max} = 24.0V[/tex]

N = 300 turns

A = l × b ( since it is a rectangular coil)

A = 6.46 cm × 5.00 cm

A = 0.0646 m × 0.05 m

A = 0.00323 m²

ω = 400 rpm = (400/60)×2π rad/s

ω = 41.8879 rad/s

Putting all the parameters into the formula

[tex]B = \frac{emf_{max} }{NA\omega}[/tex]

[tex]B = \frac{24.0}{300\times0.00323\times41.8879}[/tex]

[tex]B = 0.5913T[/tex]

Hence, the field strength needed to produce a 24.0 V peak emf is 0.5913 T

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