Có một số điện trở giống nhau R0 = 3

. Cần ít nhất bao nhiêu điện trở để có một
đoạn mạch có điện trở Rtđ = 8

Answers

Answer 1

Answer:

hlo

Explanation:

hlo olz mark me as brainlest


Related Questions

Ans it fastly
i need the ans fastly ​
NO SPAM

Answers

12. C

13. A

14. B

15. D

16. D

17. B

PLEASE ASAP! I SENT A PHOTO CHECK AND TELL!

Answers

Answer:

Answer B is the correct answer: "Motion of one projectile as seen from the other is a straight line."

Explanation:

Let's write the equations of motion for each projectile, using that projectile [tex]a[/tex] is launched with velocity [tex]a[/tex] which has components associated with the angle of launching, given in x and y coordinates as: [tex]a_x\,\,and\,\,a_y[/tex].

Similarly, assume that projectile b is launched with velocity [tex]b[/tex] with components due to the launching angle = [tex]b_x\,\,and \,\,b_y[/tex]

then the equations of motion for the two projectiles launched at the same time (t) from the same spot (position that we assume to be at the origin of coordinates to simplify formulas) are:

[tex]x_a=a_x\,t\\y_a= a_y\,t-\frac{1}{2} g\,t^2\\and\\x_b=b_x\,t\\y_b= b_y\,t-\frac{1}{2} g\,t^2[/tex]

therefore, from the frame of reference of projectile "b", the x and y position of projectile "[tex]a[/tex]" would be:

[tex]x_{a\,b}= x_a-x_b= a_x\,t-b_x\,t=(a_x-b_x)\,t[/tex]  which is linear in "t"

[tex]y_{a\,\,b}=y_a-y_b= a_y\,t-\frac{1}{2} g\,t^2-\left[ b_y\,t-\frac{1}{2} g\,t^2\right]=(a_y-b_y)\,t[/tex] which is also linear in t.

Therefore the motion of one projectile with reference to the other is a straight line (answer B)

Notice as well that this two projectiles cannot collide because they have been launched together, and supposedly at different speeds and angles. The only way that they can share the same x-coordinate and the same y-coordinate at the same time "t" is if their velocity components are equal, which is not what we are told.

[tex]x_a=x_b\\a_x\,t= b_x\,t\\and\\y_a= y_b\\a_y\,t-\frac{1}{2} g\,t^2= b_y\,t-\frac{1}{2} g\,t^2\\a_y\,t=b_y\,t\\a_y=b_y[/tex]


If Bulb B burns
out, what happens?
A Bulb A and C will stay lit.

Answers

Answer: C

Explanation:

Since bulb B is burnt out, the wires can't transfer to bulb A, so that's why bulb A will burn out.

If I get it wrong, sorry. Im still learning.

A container contains 200g of water at initial temperature of 30°C. An iron nail of mass 200g at temperature of 50°C is immersed in the water. What is the final water temperature? State the assumptions you need to make in your calculations.
[Given the value of specific heat capacity of water is 4200 J kg^-1 °C^-1 and that of iron is
450 J kg^-1 °C^-1]​

Answers

Answer:

The final temperature is 31.94°

Explanation:

The mass of the water in the container m₁ = 200 g = 0.2 kg

The initial temperature of the water,  T₁₁ = 30°C

The mass of the iron, m₂ = 200 g = 0.2 kg

The temperature of the iron T₂₁= 50°C is immersed in the water,

The specific heat capacity of the water, c₁ = 4200 J/(kg·°C)

The specific heat capacity of the iron, c₂ = 450 J/(kg·°C)

Heat capacity relation is given by the formula;

Heat capacity Q = Mass, m × Specific heat capacity, c × Temperature change, (T₂ - T₁)

Given that energy can neither be created nor destroyed, and with the assumption that all the heat lost by the nail is gained by the water we have;

Heat lost by iron nail = Heat gained by the  water

m₁ × c₁ × (T₂ - T₁₁) = m₂ × c₂ × (T₂₁ - T₂)

Where, T₂ is the final temperature

0.2 kg × 4200 J/(kg·°C) × (T₂ - 30) = 0.2 kg × 450 J/(kg·°C) × (50° - T₂)

840·T₂ - 25200 = 4500 - 90·T₂

4500 + 25200 = 840·T₂ + 90·T₂

29700 = 930·T₂

T₂ = 29700/930 = 31.94°.

The final temperature = 31.94°.

an object is +2 m from the reference point. the object starts from rest it travels for 3 seconds and has a final position of -16 m. what is the acceleration of the object?

Answers

Answer:

Solution

Given:

initial velocity (u)=0m/s (because an object

starts from the rest)

time (t)=3sec

diatance travelled(s)=14m(16-2=14)

acceleration (a)=?

Now,

According to the formula

s=ut+1/2at^2

or,14 =0×3+1/2×a×3^2

or, 14=0+a/2×9

or, 14=9a/2

or, 9a=28

or, a=28/9

or, a=3.1 m/s^2

Therefore, the acceleration of the object is 3.1m/s^2 ans.

What distance will be traveled if you are going 0.120m/s for 30 min​

Answers

Answer:

216

you have to change the meters per second to meters per minute, so you multiply .12 by 60 and get 7.2, then you multiply 7.2 meters per minute by 30 minutes and get 216

SHOW ADEQUATE WORKINGS IN THIS SECTION

12. Wale and Lekan of 55kg and 60kg respectively ran a race of 200m.

i. Calculate their work done in KJ

ii. If wale finished the race in 25secs while Lekan finished in 30secs, calculate their

power and who is more powerful out of these two. ( g = 10m/secs)

13. A machine has a velocity ratio of 5 and is 800

/0 efficient. If the machine is carrying a load

of 200kg, what will be effort applied?


Please help me answer anyone that you understand ​

Answers

Answer:

12 i. The work done by Wale = 107.910 kJ

The work done by Lekan = 117.720 kJ

Total work done = 225.36 kJ

ii. Wale's power =  4.3164 kW

Lekan's power = 3.924 kW

Wale has more power and is more powerful than Lekan

13. 313.92 N

Explanation:

i. The work done, W = Force, F × Distance moved by the force, D

The given parameters are

The mass of Wale = 55 kg

The mass of Lekan = 60 kg

The acceleration due to gravity, g =9.81 m/s²

The motion force of Wale and Lekan are;

Motion force of Wale = 9.81 × 55 = 539.55 N

Motion force of Lekan = 9.81 × 60 = 588.6 N

The work done by Wale = 539.55 × 200 = 107910 J = 107.910 kJ

The work done by Lekan= 588.6 × 200 = 117720 J = 117.720 kJ

107910 + 117720 =225630 J = 225.36 kJ

ii. Power = Work done/time

Wale finished the race in 25 s, therefore, his power = 107910/25 = 4316.4 W

Lekan finished the race in 30 s, therefore, his power = 117720/30 = 3924 W

Wale has more power and is more powerful than Lekan

13. The velocity ratio = 5

V. R. = Distance moved by effort/(Distance moved by load)

Efficiency = 80%

Work done by effort = x

Work done by machine = Efficiency × Work done by effort  = 0.8 × x

Distance moved by effort, E = V. R. × Distance moved by load, D = 5 × D

Work done by effort = Force × Distance moved = 200×9.81× E

Work done by effort = 1962×E = 1962×E = 1962×5×D

Work done by machine = 1962 × D, when D = 1, we have;

0.8 × 1962×1 = 1569.6 J

Work done by effort = Force × Distance moved

Work done by effort = Force × 5×D = Force × 5 (D = 1)

From the principle of conservation of energy, we have;

Energy is neither created nor destroyed

Therefore

Work done by effort = Force × 5 = 1569.6 J

Force = 1569.6 /5 = 313.92 N.

Thiết bị nào sau đây không phải là nguồn điện
A. Ắc quy
B. Pin
C. Máy phát điện
D. Bóng đèn điện

Answers

shsbbsnsjsbsnsnsnsnsnsndndndnd

2. a. in which principle does simple machine works? ​

Answers

Answer:

A simple machine uses a single applied force to do work against a single load force

Ignoring the friction losses. The work done on the load is equal to the work done with the applied energy. The machine can increase the amount of output power, with a corresponding drop in the distance transported by the load.

Describe the motion of water waves.

Answers

Answer:

Water waves are an example of waves that involve a combination of both longitudinal and transverse motions. As a wave travels through the waver, the particles travel in clockwise circles. The radius of the circles decreases as the depth into the water increases.

There is no centripetal force if the object moves in a long line. True or False?

Answers

Answer:

true

Explanation:

i think it's true because according to newtons first law of motion an object continues in motion unless compelled by an external force, this external force is known as the centripetal force.

I hope this helps

What areas of the work force can science be applied to?
Select all that apply
government regulatlon
healthcare
a telemarketing
environmental engineering
banking

Answers

Answer:

All of the work of life

Explanation:

In all works of life science can be applied, in-fact science has already been applied already, even in the humanities, social sciences and art related studies sciences is being applied,

    Furthermore, the application of science and technology knows no boundaries, and as science is advancing day by day, expanding to new frontiers and breaking new limits so is it application to all works of life and relevance everyday.

Trey is testing a properly working resistor in a circuit and finds its value to be far lower than he expects what’s a likely error
A. The resistor is faulty

B. The circuit is energized

C. He didn’t cut a lead on the resistor

D. The resistor is installed backwards

Answers

D. The resistor is installed backwards

A car is driving at 99 km/h, calculate the distance it travels in 70 minutes.

Give your answer in correct SI units rounded to 0 decimal places.

Answers

Answer:

The distance the car travels is 115500 m in S.I units

Explanation:

Distance d = vt where v = speed of the car and t = time taken to travel

Now v = 99 km/h. We now convert it to S.I units. So

v = 99 km/h = 99 × 1000 m/(1 × 3600 s)

v = 99000 m/3600 s

v = 27.5 m/s

The speed of the car is 27.5 m/s in S.I units

We now convert the time t = 70 minutes to seconds by multiplying it by 60.

So, t = 70 min = 70 × 60 s = 4200 s

The time taken to travel is 4200 s in S.I units

Now the distance, d = vt

d = 27.5 m/s × 4200 s

d = 115500 m

So, the distance the car travels is 115500 m in S.I units

Drag each tile to the correct box.
Arrange in the correct order the actions and reactions that occur when the
Federal Reserve uses the required reserve ratio in its expansionary
monetary policy
Hiles
ince
Households and businesses
take out more loans,
GDP increases
The money supply increases.
Banks have more money
to lend

Answers

Federal reserve decreases the required reserve ratio.

Banks have more money to lend

Money supply increases

Interest rates fall

Households and business take out more loans

Purchases and investments increases.

There are two types of monetary policies, Expansionary and Contractionary.

The government decides the monetary policy based on the economy of a country. The government will have expansionary monetary policy when it requires more money in the economy. Interest rates are lowered and money supply is increased. This results increase in Gross Domestic products of the country and the economy strengthens.

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Answer:

Below is the answer

Explanation:

A ball is thrown vertically upwards at an initial speed of
23
m s

1
. What is the displacement of the ball 3 seconds after it was thrown?

Answers

Answer:

114m

Explanation:

s=ut + 1/2 at^2

s=23 m/s ×3s + 1/2×3×3s^2×10m/s^2

= (69+45)m

= 114m

A 26-foot ladder is placed against a wall. If the top of the ladder is sliding down the wall at -2 feet per second (note that the rate is negative because the height is decreasing). At what rate is the bottom of the ladder moving away from the wall when the bottom of the ladder is 10 feet away from the wall?

Answers

Answer:

Dx/dt  = 4,8 f/s

Explanation:

The ladder placed against a wall, and the ground formed a right triangle

with x and h the legs and L the hypothenuse

Then

L² = x² + h²          (1)

L = 26 f

Taking differentials on both sides of the equation we get

0  = 2x Dx/dt  + 2h Dh/dt    (1)

In this equation

x = 10   distance between the bottom of the ladder and the when we need to find, the rate of the ladder moving away from the wall

Dx/dt is the rate we are looking for

h = ?    The height of the ladder when  x = 10

As    L²  =  x²  + h²

h²  =  L²  -  x²

h²  =  (26)²  - (10)²

h²  =  676  -  100

h²  = 576

h = 24 f

Then equation (1)

0  = 2x Dx/dt  + 2h Dh/dt

2xDx/dt  = -  2h Dh/dt

10 Dx/dt  = - 24 ( -2 )      ( Note the movement of the ladder is downwards)

Dx/dt  =  48/10

Dx/dt  = 4,8 f/s

Como surgiu a capoeira?

Answers

La capoeira se desarrolló en Brasil, derivada de las tradiciones traídas a través del Océano Atlántico por africanos esclavizados y alimentadas por el ardiente deseo de libertad. Pronto se practicó ampliamente en las plantaciones como un medio para romper los lazos de la esclavitud, tanto física como mentalmente.

Please Help
A skydiver jumps out of a hovering helicopter, so there is no forward velocity. Use this information to answer questions. Ignore wind resistance for this exercise.
3. What is the skydiver's velocity after one second? Show your work and include direction.

Answers

Answer:

The velocity and direction after 1 second is 8.1 m/s downwards

Explanation:

The equation of motion for an object in free fall can be written as follows;

v = u + g×t

Where;

v = The final velocity of the object

u = The initial velocity of the object = 0 m/s

g = The acceleration due to gravity = 9.81 m/s²

The velocity after one second is given by the velocity equation as follows;

v = 0 + 9.81 m/s² * 1 s = 9.81 m/s

The direction of the is downwards due to the attraction by the Earth's gravitational field which acts towards the Earth's center

Therefore, the velocity and direction after 1 second is 8.1 m/s downwards.

What is necessary for a ball to be in translational equilibrium?

Answers

Answer:

In order to be in translational equilibrium, the net force (sum of the forces) must be 0.

A 4-N object object swings on the end of a string as a simple pendulum. At the bottom of the swing, the tension in the string is 9 N. What is the magnitude of the centripetal acceleration of the object at the bottom of the swing? Give the answer as a function of the acceleration due to gravity, g.

Answers

Answer:

Explanation:

Given mg = 4N .

m = 4 / g

At the bottom of the swing let centripetal acceleration be a

T - mg = ma

9 - 4 = ma

5 = 4 a  / g

a =  5g / 4

Which example best describes a restoring force?
any force that is applied to a spring to change its length
the force applied to stretch a spring and increase its length
the force applied to restore a spring to its original length
the force applied to compress a spring and shorten its length

Answers

Answer:

the force applied to restore a spring to its original length

Explanation:

if you ran 15 km/hr for 2.5 hours, how much distance would you cover?

Answers

Answer: 37.5 km

Explanation:

The question is that

If you ran 15 km/hr for 2.5 hours, how much distance would you cover ?

Where

Speed = 15 km/ hr

Time = 2.5 hours

Using the formula for speed.

Speed = distance/time

Substitute speed and time into the formula

15 = distance/ 2.5

Make distance the subject of formula by cross multiplying.

Distance = 15 × 2.5

Distance = 37.5 km.

With the aid of a suitable diagram, explain what is meant by an electromagnetic wave.

Answers

Answer:

Electromagnetic waves or EM waves are waves that are created as a result of vibrations between an electric field and a magnetic field. In other words, EM waves are composed of oscillating magnetic and electric fields.

Explanation:

How do parts of a fancy cup (metal like cup) work together to keep a drink cold?

Answers

Answer:

“They may feel colder but that's only an illusion,” Dr. Begley says. “Copper mugs actually absorb heat from the room faster than a glass.” Copper is an excellent thermal conductor, meaning it transfers heat from hot sources (like the room or your hand) to cold sources (like your drink) very efficiently.

Explanation:

obesity occurs due to (a) overeating of carbohydrates and fats(b) not eating enough carbohydrates and fats (c) overeating of vitamins and minerals (d) not eating enough vitamins and minerals

Answers

Answer:

B for BIG

Explanation:

carbs and fats is energy, if not being use or burned off, it'll be becomes body fat.

A car is moving on straight highway with a speed of 108 km/h.

Answers

Answer:

5.3333 sec

Explanation:

initial speed: u = 108km/hr or 30 m/s

final speed: v = 0m/s

distance travelled: s = 80m

time the car took to stop: = t sec

[tex]v^{2} - u^{2}[/tex] = 2as,

a = ([tex]v^{2} - u^{2}[/tex])/2s

a = (0-900)/160

a = -5.625 [tex]ms^{-2}[/tex]

v = u + at,

t = (v - u)/a

t= (0 - 30)/(-5.625)

t = 5.3333 sec

Which waves move fast Longitudinal waves or Transverse waves and why???

Answers

Answer:

Transverse wave

Explanation:

Its because in transverse wave the particle displacement is perpendicular to the direction of wave propagation..hope it helps you...

Which statement accurately describes electronic tools? Check all that apply

Answers

Electronic tools provide more accurate data and this data is more efficient,fast and easy to understand

Answer:

Electronic tools provide more accurate data and this data is more efficient fast and easy to understand

Hope this helps you!!

What is the approximate pressure of a storage cylinder of recovered r-410a that does not contain any non-condensable impurities and is stored in a room where the temperature is 80°f?

Answers

Answer:

173psig

Explanation:

The storage cylinder of recovered R-410A is mixture of difluoromethane and pentafluoroethane which is used as a refrigerant in air conditioning application. The refrigeration sector has low temperatures for installation. The pressure of cylinder at 80 F will be 173 psig. The pure refrigerants have inside a container have saturation temperature which is equal to ambient temperature.

A containment canister of recovered r-410a has an estimated pressure of 173psig.

The retrieved R-410A preservation container is a blend of difluoromethane and pentafluoroethane, that is used as a compressor in air conditioning systems.

Assembly conditions in the freezer industry are extremely low. At 80 degrees Fahrenheit, the cylinder pressure will be 173 pounds per square inch.

The specific heat capacity of pure refrigeration systems within a cylinder is the same as the room temperature.

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