With neat circuit diagrams where possible show any two (2) ways of direct current motor
excitations,

Answers

Answer 1
Mainly there are two types of DC Motors. One is Separately Excited DC Motor and other is Self-excited DC Motor. The self-excited motors are further classified as Shunt wound or shunt motor, Series wound or series motor and Compound wound or compound motor. The dc motor converts electrical power into mechanical power.

Related Questions

A balloon pops, making a loud noise that startles you. What kind of energy best describes this experience?

A. Thermal Energy
B. Sound Energy
C. Gravitational Energy
D. Radiant Energy

Answers

The correct answer is b

In higher mass stars, repeating cycles of fusion will create heavier elements in layers
until which element is created at the center of the core?

hydrogen

iron

uranium

helium

Answers

the element is iron.

Two identical loudspeakers 2.30 m apart are emitting sound waves into a room where the speed of sound is 340 m/s. Abby is standing 5.00 m in front of one of the speakers, perpendicular to the line joining the speakers, and hears a maximum in the intensity of the sound. Part A What is the lowest possible frequency of sound for which this is possible

Answers

Answer:

By the Pythagorean Theorem the distances from the speakers os

5 and 5.5 (rounding) meters   - let y be the wavelength in the solution

n y = 5      n is number of wavelengths from speaker

(n + m) y = 5.5      m must be integral for constructive interference

m y = .5       subtracting equations

m = 2      and y = ,25   for the above conditions

(n + 2) y = 5.5     substituting for m

n = 5.5 / .25 - 2 = 20

f = v / y     using frequency of sound

f = 340 / .25 = 1360 / sec    for lowest frequency

Check: D1 = y n  = ,25 * 20 = 5

and D2 = .25 * 22 = 5.5     for the distances traveled

for the long life cells we have to connect them in ____ combination​

Answers

Answer:

Parallel combination.

for the long life cells we have to connect them in parallel combination

hope it is helpful to you

A cheetah is running in a straight line in pursuit of prey. The cheetah's mass is 63.9 kg. Through its running motion, assume the cheetah experiences a constant forward force of 609.1 N. Also, assume the cheetah experiences a constant 107.9 N air resistance force that is opposite its motion. What is the magnitude of the cheetah's acceleration, in units of m/s2?

Answers

Answer:

a = 7.84 m / s²

Explanation:

For this exercise let's use Newton's second law

          F - fr = m a

indicate that the force is F = 609.1 N and the friction force is fr = 107.9 N and is constant

         a = [tex]\frac{F - fr}{m}[/tex]

let's calculate

          a = [tex]\frac{ 609.1 - 107.9 }{63.9}[/tex]

          a = 7.84 m / s²

In another version of the "Giant Swing", the seat is connected to two cables as shown in the figure (Figure ), one of which is horizontal. The seat swings in a horizontal circle at a rate of 39.3 rev / m * i * n

If the seat weighs 268 N and a 896-N person is sitting in it, find the tension in the horizontal cable

If the seat weighs 268 N and a 896-N person is sitting in it, find the tension in the inclined cable

Answers

Answer:Solution to 47E Step 1 Angular velocity of the swing=32rpm Weight of the seat =255N Weight of the person =825N Total weight =255+825=1080N Radius =7.5m

Explanation:

The v-t graph of a moving body is given below. The distance covered by the body in

the first 40s is _________and its acceleration during the last 40s is _____________.


a) 3200m; 2ms-1

b) 700m; -2ms-2

c) 900m; - 2ms-2

d) 900m; 2ms-2​

Answers

Answer: The correct answer is a) 3200 m, [tex]-2m/s^2[/tex]

Explanation:

Speed is defined as the ratio of distance travelled to the time taken. The equation follows:

[tex]\text{Speed}=\frac{\text{Distance travalled}}{\text{Time taken}}[/tex]

From the graph:

Speed for the first 40 s, v = 80 m/s

Time taken, t = 40 s

Putting values in above equation, we get:

[tex]\text{Distance travalled}=(80 m/s\times 40s)=3200 m[/tex]

Acceleration is defined as the ratio of change of velocity to the change of time. The equation follows:

[tex]\text{Acceleration}=\frac{\Delta v}{\Delta t}=\frac{v_2-v_1}{t_2-t_1}[/tex]

From the graph, for the last 40 sec:

Initial velocity, [tex]v_1[/tex] = 80 m/s

Final velocity, [tex]v_2[/tex] = 0 m/s

Initial time, [tex]t_1[/tex] = 40 s

Final time, [tex]t_2[/tex] = 80 s

Putting values in above equation, we get:

[tex]\text{Acceleration}=\frac{(0-80)m/s}{(80-40)s}\\\\\text{Acceleration}=\frac{-80m/s}{40s}=-2m/s^2[/tex]

Hence, the correct answer is a) 3200 m, [tex]-2m/s^2[/tex]

resolve the vector shown below into its components

Answers

Answer:

ans: option A

Explanation:

components along x- axis is -3x and along x- axes is -2y

now use triangle law of vector addition

The triceps muscle in the back of the upper arm extends the forearm. This muscle in a professional boxer exerts a force of 2.00\times 10^32.00×10 ^3 N with an effective perpendicular lever arm of 3.00 cm, producing an angular acceleration of the forearm of 120 rad/s^2 .
What is the moment of inertia of the boxer's forearm?

Answers

Answer:

Explanation:

From the given information:

The torque produced due to the force can be expressed as:

[tex]\tau = F \times r[/tex]

where;

[tex]\tau[/tex] = torque

F = force exerted

r = lever's arm radius

[tex]\tau[/tex] = [tex]2.00 \times 10^3 \times 0.03 m[/tex]

[tex]\tau[/tex] = 60 N.m

However, equating the torque with the moment of inertia & angular acceleration, we use the equation:

[tex]\tau[/tex] = I∝

60 Nm = I × 120 rad/s²

I = 60 Nm/120 rad/s²

I = 0.5 kg.m²

A hockey puck is sliding across the ice with an initial velocity of 25 m/s. If the coefficient of friction between the hockey puck and the ice is 0.08, how much time (in seconds) will it take before the hockey puck slides to a stop

Answers

Answer: 31.89seconds

Explanation:

Based on the information given, we are meant to calculate deceleration which will be:

t = V/a

where, a = mg

Therefore, t = V/mg

t = 25/0.08 × 9.8

t = 25/0.784

t = 31.89seconds

Therefore, the time that it will take before the hockey puck slides to a stop is 31.89seconds.

The colors that make up white light are called what?​

Answers

Answer:

The ROYGBIV

Explanation:

R - red

O - orange

Y - yellow

G - green

B - blue

I - indigo

V - violet

If a piece of an object is dropped down vertically is the moment of inertia gonna be 0? And why?

Please answer I really need this!!

Answers

Answer:

The object is dropped, we know the initial velocity is zero. Once the object has left contact with whatever held or threw it, the object is in free-fall. Under these circumstances, the motion is one-dimensional and has constant acceleration of magnitude g.

No so sure

Explanation:

Hope it helps

The power in an electrical circuit is given by the equation P= RR, where /is the current flowing through the circuit and Ris the resistance of the circuit. What is the current in a circuit that has a resistance of 100 ohms and a power of 15 watts?

[pleas ee helpppp)​

Answers

I= 0.39 A

OPTION B is the correct answer.

how is the process that generates energy in the suns core different from an explosion caused by a chemical reaction

Answers

Answer:

[tex]$E = m{c^2}$[/tex]

Explanation:

• The explosion caused by chemical reaction involves conversion of chemical energy into heat and sound, but the total mass of atoms participating in the reaction remains constant.

• In the nuclear fusion reaction, the one happening in the core of the sun, mass is directly converted into energy by the equation [tex]E=mc^{2}[/tex]

Hence, mass remains constant, it just converts in to velocity.

Learn more about nuclear fusion here:

https://brainly.com/question/982293

44.7
When Xavier places his hands near a light bulb, he notices that certain areas around the light bulb are warmer than
others. Which best explains this?
The areas to the sides of the light bulb are warmest because of conduction,
O The areas to the sides of the light bulb are warmest because of convection,
The area directly above the light bulb is warmest because of conduction,
The area directly above the light bulb is warmest because of convection.
Save and Exit
Submit
Mark this and retum
Nex

Answers

Answer:

The area directly above the light bulb is warmest because of convection.

Explanation:

if all the sides of the bulb are equally close to the light source inside the bulb, all area of the bulb would be equally heated by conduction. however, convection heating mainly heats up the surface above the light source. in convection heating, the air above the surface of the light source get heated by the light source and expands, casuing it to be less dense and rise to the top of the bulb. colder denser air at the top of the bulb sink to the light source adn gain heat and expands, becoming less dense. this process repeats and the surface above the light source becomes the warmest due to convection heating

what is simple definition of democracy​

Answers

it's a form of government where people elect their representatives

Answer:

The word democracy itself means rule by the people.


How much power does it take to lift 70.0 N to 5.0 m high in 5.00 s?

Answers

Answer:

Power = 70 W

Explanation:

Given that,

Force, F = 70 N

Height, h = 5 m

Time, t = 5 s

We need to find the power of the object. We know that,

Power = work done/time

Put all the values,

[tex]P=\dfrac{Fd}{t}\\\\P=\dfrac{70\times 5}{5}\\\\P=70\ W[/tex]

So, the required power is 70 W.

A ball player catches a ball 3.55 s s after throwing it vertically upward. with what speed did he throw it

Answers

Answer:

i believe he threw the ball up at about 18 mph

Explanation:

You throw a stone straight down from the top of a tall tower. It leaves your hand moving at 8.00 m/s, Air resistance can be neglected. Take the positive -direction to be upward, and choose y 0 to be the point where the stone leaves your hand. Find the stone's position 1.50s after it leaves your hand.
Express your answer with the appropriate units.
Find the y-component of the stone's velocity 1.50 s after it leaves your hand. Express your answer with t0he appropriate units.

Answers

Answer:

The velocity after 1.5 s is 22.7 m/s downwards.

Explanation:

Initial velocity = - 8 m/s

acceleration, a = - 9.8 m/s2

time, t = 1.5 s

Use first equation of motion

v = u + at

v = - 8 - 9.8 x 1.5

v = - 8 - 14.7

v = - 22.7 m/s  

Thus, the velocity after 1.5 s is 22.7 m/s downwards.

Which of the following statements regarding the warming of the troposphere (i.e., the lower atmosphere) are TRUE (choose all that apply):
a. Conduction only warms the shallow layer of air within a few centimeters of the ground
b. The troposphere is heated mainly from above
c. Atmospheric gases do not readily absorb solar radiation
d. The troposphere is heated mainly by direct molecule-to-molecule contact
e. Condensation of water vapor plays a role in heating the lower atmosphere
f. Oxygen and nitrogen readily absorb and emit terrestrial radiation
g. Convection distributes heat vertically

Answers

Answer: • Conduction only warms the shallow layer of air within a few centimeters of the ground

• Atmospheric gases do not readily absorb solar radiation

• Condensation of water vapor plays a role in heating the lower atmosphere.

• Convection distributes heat vertically

Explanation:

The statements regarding the warming of the troposphere that are true include:

• Conduction only warms the shallow layer of air within a few centimeters of the ground

• Atmospheric gases do not readily absorb solar radiation

• Condensation of water vapor plays a role in heating the lower atmosphere.

• Convection distributes heat vertically.

Therefore, the correct options are A, C, E and G.

Conduction only warms the shallow layer of air within a few   centimeters of the ground

Atmospheric gases do not readily absorb solar radiation

Condensation of water vapor plays a role in heating the lower atmosphere.

Convection distributes heat vertically

What is troposphere?

The lowest layer of the atmosphere of the earth is the troposphere. Most of the mass (about 75-80%) of the atmosphere is in the troposphere.

Most types of clouds are found in the troposphere, and almost all weather occurs within this layer.

The statements regarding the warming of the troposphere that are true include:

Conduction only warms the shallow layer of air within a few centimeters of the ground

Atmospheric gases do not readily absorb solar radiation

Condensation of water vapor plays a role in heating the lower atmosphere.

Convection distributes heat vertically.

Thus a,c,e,g are the correct statements regarding the warming of the troposphere

To know more about Troposphere follow

https://brainly.com/question/25526298

factors that favour mining in South Africa​

Answers

Answer:

According to the data, factors influencing mining investment in South Africa's favour are the availability of labour and skills, the quality of the country's infrastructure, the quality of its geological database, and the State's environmental regulations.

A Michelson interferometer operating at a 400 nm wavelength has a 3.70-cm-long glass cell in one arm. To begin, the air is pumped out of the cell and mirror M2 is adjusted to produce a bright spot at the center of the interference pattern. Then a valve is opened and air is slowly admitted into the cell. The index of refraction of air at 1.00 atm pressure is 1.00028.
How many bright-dark-bright fringe shifts are observed as the cell fills with air?

Answers

Answer:

[tex]m=42\ fringes[/tex]

Explanation:

From the question we are told that:

Wavelength [tex]\lambda=400nm[/tex]

Length of cell arm [tex]h=3.70cm[/tex]

Refraction of air at  at 1.00 atm pressure [tex]n=1.00028.[/tex]

Generally the equation for Number of shifts is mathematically given by

[tex]m=N-N_o[/tex]

Since

[tex]N_0=\frac{2t}{\lambda_0}[/tex]

Therefore

[tex]m=\frac{2t}{\lambda_0/n}-\frac{2t}{\lambda_0}[/tex]

[tex]m=\frac{2t}{\lambda_0} n-1[/tex]

[tex]m=\frac{2(3.7*10^{-2})}{400*10^{-9}}*(1.00028-1)[/tex]

[tex]m=51.8[/tex]

[tex]m=42\ fringes[/tex]

what is the main function of a step-up and step-down transformers​

Answers

Answer:

Explanation:

The difference between step-up and step-down transformer is given below:-

Step-up transformer  

i) It increases the voltage.

ii) It decreases the current strength.

iii) It has a greater number of turns in secondary as compared to the primary.

iv) The wire of primary is thicker than that of the secondary coil.

Step-down transformer

i) It decreases the voltage.

ii) It increases the current strength of the secondary.

iii) It has less number of turns in secondary as compared to the primary.

iv) The wire of the secondary coil is thicker than that of the primary coil.

A 3.7-kg object is acted on by two forces. One of the forces is 11 N acting toward the
east. What is the other force if the acceleration of the object is 1.0 m/s2 toward the east?

Answers

Answer:

7.3 newtons to the west

Explanation:

3.7kg × 11a - 3.7kg × ? = 3.7n

Suppose 4 J of work are needed to stretch a spring 14 cm from its natural position. How much work is needed to stretch it 20 cm from its natural position

Answers

Answer:

8.16 J

Explanation:

Applying,

W = ke²/2................. Equation 1

Where W = work done in stretching the spring, k = spring constant, e = extension

make k the subject of the equation

k = 2W/e²................ Equation 2

From the question,

Given: W = 4 J, e = 14 cm = 0.14 m

Substitute these values into equation 2

k = 2(4)/0.14²

k = 8/0.0196

k = 408.16 N/m

If stretchd 20 cm from its natural length,

Therefore,

e = 20 cm = 0.2 m

W = 408.16(0.2²)/2

W = 8.16 J

An alpha particle consists of two protons and two neutrons. How will the emission of an alpha particle affect the following:

a. The atomic number of the atom: _______Atomic Number will go down_______
b. The mass number of the atom: ___Mass number will go down____________

Answers

Answer:

a) The atomic number decreases by 2 units

b) the atomic mass decreases by 4 units

Explanation:

An alpha particle is a helium nucleus, which is why it is made up of two positive protons and two negative neutrons, the mass of the particles is almost the same.

a) The atomic number decreases by 2 units

b) the atomic mass decreases by 4 units


Can somebody please help

Answers

Answer:

Explanation:

part A: C

part B: B

A house has well-insulated walls. It contains a volume of 105 m3 of air at 305 K.
Consider heating it at constant pressure. Calculate the energy required to increase the temperature of this diatomic ideal gas by 0.7

Answers

Answer: [tex]85.46\ kJ[/tex]

Explanation:

Given

Volume of air [tex]V=105\ m^3[/tex]

Temperature of air [tex]T=305\ K[/tex]

Increase in temperature [tex]\Delta T=0.7^{\circ}C[/tex]

Specific heat for diatomic gas is [tex]C_p=\dfrac{7R}{2}[/tex]

Energy required to increase the temperature is

[tex]\Rightarrow Q=nC_pdT\\\\\Rightarrow Q=n\times \dfrac{7R}{2}\times \Delta T\\\\\Rightarrow Q=\dfrac{7}{2}nR\Delta T\\\\\Rightarrow Q=\dfrac{7}{2}\times \dfrac{PV}{T}\times \Delta T\quad [\text{using PV=nRT}][/tex]

Insert the values

[tex]\Rightarrow Q=\dfrac{7}{2}\times \dfrac{1.01325\times 10^5\times 105}{305}\times 0.7\\ \text{Assuming air pressure to be atmospheric P=}1.01325\times 10^5\ N/m^2\\\\\Rightarrow Q=0.8546\times 10^5\\\Rightarrow Q=85.46\ kJ[/tex]

How would an observer on train A, which is moving at nearly the speed of light, view a clock on train B, which is moving at the same speed and in the same direction?

A. The clock on train B would appear narrower and run more slowly.
B. The clock on train B would appear to be the same width and to run at the same rate. C. The clock on train B would appear narrower and run faster.
D. The clock on train B would appear wider and run more slowly.

Answers

Answer:

B.

Explanation:

If both train A and train B are moving in the same direction and the exact same speed then from an observer's viewpoint within either train everything would seem as though it is not moving. Therefore, the clock on train B would appear to be the same width and to run at the same rate. In order for this to be the case the speed of both trains would need to be exactly the same, any difference in speed will cause the clock on the opposite train to appear distorted and run either faster or slower depending on the speed of the train you are on.

Answer:

The trains are moving at the same speed, so the answer is A.

Three identical boxcars are coupled together and are moving at a constant speed of 28.0 m/sm/s on a level, frictionless track. They collide with another identical boxcar that is initially at rest and couple to it, so that the four cars roll on as a unit. Friction is small enough to be neglected.

Required:
a. What is the speed of the four cars?
b. What percentage of the kinetic energy of the boxcars is dissipated in the collision?
c. What happened to this energy?

Answers

Answer:

A) v = 21 m /s

B) 25%

C) ) on collision, this energy in the question appears in the form of the following namely; sound energy, heat energy etc

Explanation:

A) Let m be the mass of any of the cars

Thus:

mass of the three cars = 3m

Formula for kinetic energy = ½mv²

Thus, Kinetic energy of 3 identical and coupled cars = ½ x 3m x 28² = 1176 m

KE = 1176 m

Now mass of 4 coupled cars together = 4m

From conservation of linear momentum, we can find the speed of the four cars. Thus;

m1v1 = m2v2

We are told that the 3 coupled moved together with a speed of 28 m/s

Thus;

4m × v = 3m × 28

v = 3m x 28 / 4m

v = 21 m /s

B) from earlier, we saw the formula for kinetic energy. Thus, kinetic energy with of mass of 4 coupled cars together. Thus;

K = ½ x 4m x 21²

K = 882m

Loss of kinetic energy

ΔK = 1176 m - 882 m

ΔK = 294 m

Therefore, percentage of loss is;

%loss = (294 / 1176 ) x 100

%loss = 25 %

C) on collision, this energy in the question appears in the form of the following namely; sound energy, heat energy etc

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