Hai xe chuyển động trên cùng một đoạn đường , khi xe (1) ở A thì xe (2) ở B phía trước với AB=5km . Xe (1) đuổi theo xe (2) . Tại C cách B một đoạn BC=10km thì xe (1) đuổi kịp xe (2) . Tìm tỉ số vận tốc của hai xe

Answer:

3 ohms

Explanation:

Applying,

R₁₀₀ = R₀(1+αΔT).............. Equation 1

Where α = coefficient of resistance, ΔT = change in temperature, R₁₀₀ and R₀ = Resistance at 100°C and 0°C respectively

make R' the subject of the equation

R₀ = R₁₀₀/(1+αΔT).............. Equation 2

From the question,

Given:  R₁₀₀ = 4.2 ohm, α = 0.004 per degree, ΔT = 100-0 = 100°C

Substitute these values into equation 2

R₀ = 4.2(1+0.004×100)

R₀ = 4.2/1.4

R₀ = 3 ohms

Answer:

The given details in the question are;

The device with which the object is pulled = A spring balance

The reading on the spring balance as the object is pulled = 20 N = The force with which the object is pulled

The speed with which the object is moving = Constant speed (zero acceleration)

The net force acting on the object = Zero

The forces acting on the object are;

The force of pull and the friction force

Therefore;

The force of pull + The friction force = 0

The force of pull = 20 N

∴ 20 N + The friction force = 0

The friction force = 0 - 20 N = -20N

The magnitude of the friction force = 20 N = The force of pull

(The negative sign in the value of the friction force (-20 N), indicates that the direction of the friction force is opposite to the direction of the force of pull)

Explanation:

Answer:

-272.1

Explanation:

1K − 273.15 = -272.1°C

Answer: Load carrying heavy vehicles have large number of wheels in order to reduce pressure on the contact patch on road. With large number of wheels, it becomes easy to distribute the entire pressure of loads in an even manner.

Explanation:

Answer:

Circuit Breaker - a protective device used to automatically blows and cuts the current when trouble in the circuit such as short circuit or overload occurs

Answer:

The independent variable is the variable the experimenter manipulates or changes, and is assumed to have a direct effect on the dependent variable. ... The dependent variable is the variable being tested and measured in an experiment, and is 'dependent' on the independent variable.

Answer: The equations in column A is matched with gas laws in column B as follows:

21. PV = nRT : (g) Ideal gas law

22. [tex]V_{1}n_{2} = V_{2}n_{1}[/tex] : (f) Avogadro's law

23. [tex]P_{1}V_{1}T_{2} = P_{2}V_{2}T_{1}[/tex] : (e) Combined Gas Law

24. [tex]P_{1}T_{2} = P_{2}T_{1}[/tex] : (d) Gay-Lusaac's law

25. [tex]V_{1}T_{2} = V_{2}T_{1}[/tex] : (c) Charles' law

26. [tex]P_{1}V_{1} = P_{2}V_{2}[/tex] : (b) Boyle's law

27. [tex]\frac{v_{1}}{v_{2}} = \frac{\sqrt{MM_{1}}}{MM_{2}} = \frac{\sqrt{p_{1}}}{p_{2}}[/tex] : (a) Graham's Law of effusion

Explanation:

(A) Ideal gas law: It states that the product of pressure and volume is directly proportional to the product of number of moles and temperature.

So, PV = nRT

where,

P = pressure

V = volume

n = no. of moles

R = gas constant

T = temperature

So, [tex]P_{1}V_{1} = P_{2}V_{2}[/tex]

[tex]V \propto T\\\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}\\V_{1}T_{2} = V_{2}T_{1}[/tex]

So,  [tex]P_{1}T_{2} = P_{2}T_{1}[/tex]

So, [tex]V_{1}n_{2} = V_{2}n_{1}[/tex]

[tex]\frac{P_{1}V_{1}}{T_{1}} = \frac{P_{2}V_{2}}{T_{2}}\\or, P_{1}V_{1}T_{2} = P_{2}V_{2}T_{1}[/tex]

[tex]\frac{v_{1}}{v_{2}} = \frac{\sqrt{MM_{1}}}{MM_{2}} = \frac{\sqrt{p_{1}}}{p_{2}}[/tex]

Thus, we can conclude that equation in column A is matched with gas laws in column B as follows:

21. PV = nRT : (g) Ideal gas law

22. [tex]V_{1}n_{2} = V_{2}n_{1}[/tex] : (f) Avogadro's law

23. [tex]P_{1}V_{1}T_{2} = P_{2}V_{2}T_{1}[/tex] : (e) Combined Gas Law

24. [tex]P_{1}T_{2} = P_{2}T_{1}[/tex] : (d) Gay-Lusaac's law

25. [tex]V_{1}T_{2} = V_{2}T_{1}[/tex] : (c) Charles' law

26. [tex]P_{1}V_{1} = P_{2}V_{2}[/tex] : (b) Boyle's law

27. [tex]\frac{v_{1}}{v_{2}} = \frac{\sqrt{MM_{1}}}{MM_{2}} = \frac{\sqrt{p_{1}}}{p_{2}}[/tex] : (a) Graham's Law of effusion

Answer:

4 capacitors

Explanation:

Given

[tex]n = 5[/tex] --- conducting plates

Required

The number of capacitor (c)

This is calculated as:

[tex]c = n - 1[/tex]

So, we have:

[tex]c = 5 - 1[/tex]

[tex]c = 4[/tex]

Answer:

A stone floor feels very cold to bare feet in winter, but a carpet in the same room feels comfortably warm.This is because both the floor and the carpet have the same temperature as both are exposed to the same atmosphere. But the former conducts away the heat from the feet better than the carpet as the latter is a non-conductor. So the feet losing more heat, the floor appears cooler to the feet

Explanation:

Hope it may help you!!

Both actually have same temperature. Our feet are warm. Floor is conductor of heat while carpet is not. When we walk on floor, then floor takes away or conducts the heat from our feet, so we feel cold. While carpet doesn't do that, so we feel warm.

Answer:

The beta decay takes place.

Explanation:

The reaction of radioactivity of carbon 14 to nitrogen 14 is

There is a beta decay.  

The reaction is

[tex]C_{6}^{14}\rightarrow N_{7}^{14}+\beta _{-1}^{0}+ energy[/tex]

Here some energy is released in form of neutrino.

Evaporation and Boiling are the two vaporizations.

Evaporation is the type of vaporization that occurs at temperatures below the boiling point, whereas boiling is the type of vaporization that occurs at temperatures above the boiling point. The other type of vaporization is boiling, which occurs when a liquid is heated to the point where its vapor pressure equals the external pressure surrounding the liquid. When the liquid is heated, bubbles form within the liquid.

Hope this helps and if it does, don't be afraid to give my answer a "Thanks" and maybe a Brainliest if it's correct?  

Answer:

sample respond: Vaporization is the process by which a liquid becomes a gas. The two types of vaporization are evaporation and boiling. Evaporation takes place at the surface of a liquid, such as a puddle drying up. Boiling takes place below the surface of a liquid and causes bubbling, like a pot of water on a hot stove. Explanation:

Answer:

a)  [tex]q=4.92*10^{-8} C[/tex]

b)  [tex]m=4.026*10^{-6} kg[/tex]

Explanation:

From the question we are told that:

Separation distance [tex]d=2.65*10^{-2} m[/tex]

Acceleration 1 [tex]a_1=5.00*10^3 m/s^2,[/tex]

Acceleration 2 [tex]a_2=7.70*10^3 m/s^2,[/tex]

Mass 1 [tex]m_1=6.20*10^{-6}[/tex]

Generally the equation for Force is mathematically given by

 [tex]F=ma[/tex]

For Particle 1

 [tex]F=6.2*10^{-6} *5*10^3[/tex]

 [tex]F=0.031 N[/tex]

Also

 [tex]F=\frac{kq_1*q2}{r^2}[/tex]

Where

 [tex]q_1=q_2[/tex]

Therefore

 [tex]0.031=\frac{9*10^9*q^2}{(2.65*10^-2)^2}[/tex]

 [tex]q=4.92*10^{-8} C[/tex]

b)

Generally the equation for Force is mathematically given by

 [tex]F=ma[/tex]

 [tex]0.031=7.7*10^3[/tex]

 [tex]m=4.026*10^{-6} kg[/tex]

Answer:

physics is the study of functions, systems and and the explainable reasons why they do what they do.

Answer:

physics is the branch of science concerned with the nature and properties of matter and energy. it includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.

Explanation:

answer is in the picture above

Answer:

Measurement is the quantification of attributes of an object or event, which can be used to compare with other objects or events

Answer:

The comparison of an unknown quantity with a known quantity is called measurement

Answer:

the elements are made up of only one kind of atom, the compounds consist of two or more elements that are chemically combined, and the mixtures are physical combination of two or more substances

Answer:

Distance = 80 meters

Explanation:

Given the following data;

Speed = 72 km/hr

Time = 4 seconds

Conversion:

72 km/hr to meters per seconds = 72*1000/3600 = 72000/3600 = 20 m/s

To find the distance covered by the car;

Speed can be defined as distance covered per unit time. Speed is a scalar quantity and as such it has magnitude but no direction.

Mathematically, speed is given by the formula;

[tex]Speed = \frac{distance}{time}[/tex]

Making distance the subject of formula, we have;

[tex] Distance = speed * time [/tex]

Substituting into the above formula, we have;

[tex] Distance = 20 * 4 [/tex]

Distance = 80 meters

Answer:

option a.

Explanation:

We can think of an atom as a nucleus (where the protons and neutrons are) and some electrons orbiting it.

We also know that the mass of an electron is a lot smaller than the mass of a proton or the mass of an electron.

So, if all the protons and electrons of an atom are in the nucleus, we know that most of the mass of an atom is in the nucleus of that atom.

Then we define the mass number, which is the total number of protons and neutrons in an atom. Such that the mass of a proton (or a neutron) is almost equal to 1u

Then if we define A as the total number of protons and neutrons, and each one of these weights about 1u

(where u = atomic mass unit)

Then the weight of the nucleus is about A times 1u, or:

A*1u = A atomic mass units.

Then the correct option is:

The mass of the nucleus is approximately EQUAL to the mass number multiplied by __1__ Atomic Mass unit.

option a.

Answer:

C.) Longitudinal

Answer:

31. Respiratory System

32. Excretory System

33. Nervous System

34. Reproductive system

35. Skeleton System

Explanation:

Hope it helps you.^_^

Answer:

31. Respiratory System

32. Excretory System

33. Circulatory System

34. Reproductive System

35. Muscular and Skeletal System

Explanation:

In 35. you should write both systems since only one of them may give you half the marks.

Also do put your questions on the health section

Answer:

E

Explanation:

it has more mass

The medium in which mechanical waves will travel the slowest in is air which is gaseous medium.

A mechanical wave is a type of wave that requires material medium for its propagation.

An example of mechanical wave is sound wave because sound wave requires material medium for its propagation.

Sound waves travel fastest in solid, followed by liquid, then least in gasous medium.

Thus, the medium in which mechanical waves will travel the slowest in is air which is gaseous medium.

Learn more about mechanical waves here: https://brainly.com/question/9242091

Answer:

The coordinates of the point the bulb should be placed is (2, 0.25)

Explanation:

The given equation of a parabola is presented as follows;

(x - 2)² = 5·(y + 1)

The point the bulb should be placed is the focus of the parabolic mirror to ensure a perfect (straight) beam

The general form of the equation of a parabola is (x - h)² = 4·p·(y - k)

The coordinates of the focus of the parabola for p > 0 f = (h, k + p)

By comparison, h = 2, k = -1, and p = 5/4

∴ The coordinates of the focus of the parabola, f = (2, -1 + 5/4)  = (2, 0.25)

The coordinates of the point the bulb should be placed is at the focus, f =  (2, 0.25).

Answer: True

Explanation:

Answer:

Explanation:

The equation for Coulomb's Law is

[tex]F=\frac{kq_1q_2}{r^2}[/tex] where k is Coulomb's constant, q1 is one of the charges, q2 is another one of the charges (1 of these has to be the one in question, so we will let that be q2) and r is the distance between them squared.

First thing we are going to do is convert those microCoulombs to Coulombs (C).

q1: [tex]-53.0\mu C*\frac{.000001C}{1\mu C}=-5.3*10^{-5}C[/tex] and

q2: [tex]105\mu C*\frac{.000001C}{1\mu C}=1.05*10^{-4}C[/tex] and

q3: our main particle that we will put in for q2 in the formula converts as follows:

q3: [tex]-88.0\mu C*\frac{.000001C}{1\mu C} =-8.8*10^{-5}C[/tex]  

First we will find the charge between q1 and the main particle:

[tex]F_1=\frac{(9.0*10^9)(5.3*10^{-5})(8.8*10^{-5})}{(1.45)^2}[/tex] Notice that we did not use the negative charges here. We take the negative charge into account depending upon whether or not the charges are repelled or attracted. Both of these charges are negative, so they will repel and the answer will be made negative. Finding the first force:

[tex]F_1=-2.0*10^1N[/tex] (negative because they repel so q1 will move away from the charge in question, which is also negative)

[tex]F_2=\frac{(9.0*10^9)(1.05*10^{-4})(8.8*10^{-5})}{(.95)^2}[/tex] and the charge between these is

[tex]F_2=92N[/tex] and that is to the right, so positive. These charges are opposite, so they attract. The net force is the sum of the forces, so:

[tex]F_1+F_2:[/tex] -2.0 × 10¹ + 92 = 72N (to the right)

Answer:

a)   [tex]A=5m/s^2[/tex]

b)   [tex]V=25m/s[/tex]

Explanation:

From the question we are told that:

Velocity [tex]v=90km/h=25m/s[/tex]

Time [tex]t=5.0s[/tex]

a)

Generally From Newton's motion equation for Average acceleration is   mathematically given by

  [tex]A=\frac{V-U}{t}[/tex]

Since its from Rest Therefore

  [tex]U=0[/tex]

 [tex]A=\frac{25m/s-0}{5s}[/tex]

 [tex]A=5m/s^2[/tex]

b)

Generally the equation for Average Velocity is mathematically given by

  [tex]V=u+at[/tex]

 [tex]AT t=1.0s\\\\V=0+5(1)[/tex]

 [tex]V=5m/s[/tex]

 [tex]AT t=2.0s\\\\V=0+5(2)[/tex]

 [tex]V=10m/s[/tex]

 [tex]AT t=5.0s\\\\V=0+5(5)[/tex]

 [tex]V=25m/s[/tex]

Answer:

Cogeneration is a more efficient use of fuel or heat, because otherwise-wasted heat from electricity generation is put to some productive use. Combined heat and power (CHP) plants recover otherwise wasted thermal energy for heating.

Explanation:

Answer:

The original volume of the metal sphere is approximately 1 cm³

Explanation:

The given parameters are;

The temperature change of the metal ball, ΔT = 30°C = 30 K

The new volume of the metal ball, V₂  = 1.0018 cm³

The linear expansivity of the material ball, α = 2.0 × 10⁻⁵ K⁻¹

We have;

d₂ = d₁·(1 + α·ΔT)

Where;

d₁ = The original diameter of the metal ball

d₂ = The new diameter of the ball

From the volume of the ball, V₂, we have;

V₂ = 1.0018 cm³ = (4/3)×π×r₂³

Where;

r₂ = The new radius = d₂/2

∴ V₂ = 1.0018 cm³ = (4/3)×π×(d₂/2)³

∴ d₂ = ∛(2³ × 1.0018 cm³/((4/3) × π)) ≈ 1.241445 cm

d₁ = d₂/(1 + α·ΔT)

∴ d₁ ≈ 1.241445 cm/(1 + 2.0 × 10⁻⁵·K × 30 K) ≈ 1.24070058 cm

The original volume of the metal ball, V₁ = (4/3)×π×(d₁/2)³

∴ V₁ = (4/3)×π×(1.24070058/2)³ ≈ 0.99999902845 cm³ ≈ 1 cm³

The original volume of the metal sphere, V₁ ≈ 1 cm³.

Answer:

It's Obusively charles Babbage I guess

Answer:

Please find attached the required graph of the data points

The graph can be interpreted as showing that which was at rest starts  moving at a constant speed of 2 km/min

Explanation:

The table is presented as follows;

[tex]\begin{array}{lcl}Time \ (min)&& Distance \ (km)\\0&&0\\5&&10\\10&&20\\15&&30\\20&&40\\25&&50\\30&&60\end{array}[/tex]

The graphic representation of the above data can be created by plotting the Time on the x-axis and the Distance on the y-axis on a graph paper

The graph of the data can be created also using a spreadsheet application such as MS Excel by using the Chart function under the Insert menu, after selecting the points input into cells on the spreadsheet as shown in the attached drawing

The distance travelled by the car in a given time is found by obtaining the rate of change of the values of the graph, m, as follows;

[tex]m =\dfrac{y_{2}-y_{1}}{x_{2}-x_{1}}[/tex]

Where (y₁, x₁), and (x₂, y₂) are a pair of chosen points on the given line

When, the chosen points are (y₁, x₁) = (0, 0), and (x₂, y₂) = (30, 60), we get;

[tex]m =\dfrac{60 \, km-0 \, km}{30 \, min-0 \, min} = 2 \, km/min[/tex]

The graph can be interpreted as showing that the rate of change of the distance travelled by the car per  unit time which is the speed of the car starting from rest is 2 km/min