Which evidence best supports that a device is an electric motor?
A. Electricity flows when a coil of wire is rotated by a hand crank.
B. Electricity flows from a battery through a loop of wire which then causes a needle to move.
C. Electricity flows from a battery to loop of wire and then through a galvanometer back to the battery.
D. Electricity flows through a coil of wire that is rotating because a magnet is pushing on the coil of wire.

Answer:

Answer is explained in the explanation section below.

Explanation:

Note: This question is incomplete and lacks the necessary diagram of the circuits to solve for this question. However, I have found similar question on the internet and dragged the diagrams out of it. I have attached the diagrams of the circuits for your ease. It has two circuits to be solved. Attachment 1 refers to first circuit and Attachment 2 refers to second circuit.

Solution:

We are asked to find the potential difference and current through each resistor.

So,

Calculations for Circuit 1: Please refer to Attachment 1

First we need to find the Resistance:

Req = [tex]\frac{9 . 6}{9+6} +3[/tex]

R = 6.6 Ohm

Now, we know that:

V = IR

So,

I = V/R

V = 12 V

I = 12 V/ 6.6 ohm

I = 1.82 Amperes.

Now,

The Potential Difference through 3 ohm resistor:

P.D = [tex]V_{3}[/tex] = 1.82 x 3

[tex]V_{3}[/tex] = 5.45 V

Now,

The Potential Difference through 6 ohm and 9 ohm resistor:

[tex]V_{6/9}[/tex] =  12V - 5.45V

[tex]V_{6/9}[/tex] =  6.545V

Now,

The current through 6 ohm is:

[tex]I_{6}[/tex] = [tex]\frac{6.545}{6}[/tex]

[tex]I_{6}[/tex] = 1.09 A

Now,

The Current through 9 ohm is:

[tex]I_{9}[/tex]  = [tex]\frac{6.545}{9}[/tex]

[tex]I_{9}[/tex]  = 0.72 A

Similarly,

Calculations for Circuit 2: Please refer to attachment 2:

Req = [tex]\frac{(30+50).90}{90+(30+50)} +20[/tex]

Req = 62.35 ohm

I = V/R

I = 12 V/ 62.35ohm

I = 0.192 Amperes.

Now,

The The Potential Difference through 20 ohm resistor:

[tex]V_{20}[/tex] = 20 x 0.192

[tex]V_{20}[/tex] = 3.849 V

Now,

The The Potential Difference through 90 ohm resistor:

[tex]V_{90/(30+50)}[/tex] = 12 - 3.849

[tex]V_{90/(30+50)}[/tex] = 8.150

Now,

The Current through 90 ohm is:

[tex]I_{90}[/tex]  = 8.1509/90

[tex]I_{90}[/tex] = 0.0905 Amperes

Now,

The Current through 30 and 50 ohm is:

[tex]I_{30/50}[/tex] = 0.192 - 0.0905

[tex]I_{30/50}[/tex]  = 0.101 A

Now,

The Potential Difference through 50 ohm resistor:

[tex]V_{50}[/tex] = 50 x 0.101

[tex]V_{50}[/tex]  = 5.094 V

The Potential Difference through 30 ohm resistor:    

[tex]V_{30}[/tex] = 30 x  0.101

[tex]V_{30}[/tex] = 3.0566 V

Answer:

the magnitude of the constant acceleration is 6.98 m/s²

Explanation:

Given;

distance traveled at a constant velocity, d = 130 m

time of motion, t = 4.9 s

The constant velocity is calculated as;

[tex]v = \frac{d}{t} \\\\v = \frac{130}{4.9} \\\\v = 26.53 \ m/s[/tex]

The car comes to a stop in 3.8 s.

When the car comes to a complete stop, the final velocity of the car will be zero.

the constant acceleration is calculated as;

v = u + at

0 = u + at

at = -u

a = -u/t

a = (-26.53) / (3.8)

a = -6.98 m/s²

Therefore, the magnitude of the constant acceleration is 6.98 m/s²

Answer:

67.17 m

Explanation:

From the question given above, the following data were obtained:

Initial velocity (u) = 32 m/s

Angle of projection (θ) = 20°

Acceleration due to gravity (g) = 9.8 m/s²

Range (R) =?

The range can be obtained as follow:

R = u²Sine 2θ / g

R = 32² × Sine (2×20) / 9.8

R = 1024 × Sine 40 / 9.8

R = (1024 × 0.6428) / 9.8

R = 67.17 m

Thus, the range of the ball is 67.17 m

Answer: Change occurs when forces in one direction exceed forces in opposing direction

Explanation:

Force field analysis is the basic tool typically used in root cause analysis which enable an individual to take certain action after the identification of the root cause.

According to force-field analysis, there is a change when the forces in one direction exceed the forces in opposing direction.

Answer:

Positive charge is attracted to the neutral object.

Explanation:

Recall ; Like charges repel, unlike charges attract. This phrase simply means (positive (+) is attracted to negative (-ve) and vuc versa while both positive, positive and negative, negative charge repel.

For a neutral object. The quantity of positive charge equals the quantity of negative charges. This simply means a neutral object contains charges as well, which are usually scattered or randomly aligned.

Therefore, when a positive charge is brought near a neutral body, the order of alignment of the charges change, with the negative charge all moving towards the direction of the positively charged body and the positive charges in the neutral body aligning in the opposite direction.

The charge will be attracted.

As you may know, opposite charges attract (and equal charges repel).

So, when you put a positive charge near a neutral material, all the negative charges in the material will move towards the surface of the material closer to the positive charge (and the positive charges in the material will move away).

Now the charge in the material is not homogeneous, so the positive charge will see a negatively charged surface near it, and it will be attracted to that surface.

Thus we can conclude that as a positive charge is brought near a neutral, insulating piece of material, the charge will be attracted towards it.

If you want to learn more about electromagnetic forces, you can read:

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Answer:

Explanation:

Work done by janitor = increase in potential energy of book

Potential energy = mgh , m is mass  , h is displacement in height and g is acceleration due to gravity .

here displacement in height of book = 2.6 - 1.3 = 1.3 m

so h = 1.3 m

m = mass of the box

increase in potential energy of box = m x 9.8 x 1.3

= 12.74 m

Work done by janitor = 12.74 m Joule .

Answer:

Oppressors have a repressive attitude toward others. They have a need for power and dominance.

Explanation:

Oppression is the painful experience of deliberate arbitrariness, violence and abuse of power inflicted on an individual, society or group of people. The term repression is often used synonymously for this.  

Oppression arises from the general, also unconscious, assumption that a certain group of people is inferior or without rights. Oppression is seldom limited to governmental activities. Individuals can also be victims of oppression if they lack the solidarity of a social group.

Oppressive individuals, in turn, are those who exert repression on others. They are generally narcissistic and megalomaniacal people, who have a wrong self-perception of their virtues and negatively weigh the virtues of other people.

Answer:

the frequency of the beats is 8.7687 kHz

Explanation:  

Given the data in the question;

The frequency for stationary source and moving observer is;

f' = f( 1 +( v_observer/v_sound))

we know that, speed of sound in dry air =  343 m/s

so we substitute

f' = 41.2 kHz( 1 + (33.0 m/s / 343 m/s) ) = 41.2kHz( 1 + 0.0962) = 41.2kHz(1.0962)

f' = 45.1634 kHz

Now the frequency for stationary observer and moving source with frequency f' will be

f" = f'( 1 / (1 - ( v_observer/v_sound)))

45.1634 kHz( 343 / 343 - 33)

we substitute

f" = 45.1634 kHz( 1 / (1 - (33.0 m/s / 343 m/s)))

f" = 45.1634 kHz( 1 / (1 - 0.0962))

f" = 45.1634 kHz( 1 / 0.9038 )

f" = 45.1634 kHz( 1.1064 )

f" = 49.9687 kHz

Now the beat frequency will be;

f_beat = f' - f

we substitute

f_beat = 49.9687 kHz - 41.2 kHz

f_beat = 8.7687 kHz

Therefore, the frequency of the beats is 8.7687 kHz

Answer:

the power used by the person is 17 W.

Explanation:

Given;

applied force, F = 51 N

distance through which the chair is used, d = 5 m

time of motion, t = 15 s

The power used by the person is calculated as;

[tex]P = FV\\\\P = F \ \times \ \frac{d}{t} \\\\P = 51 \ \times \ \frac{5}{15} \\\\P = 17 \ W[/tex]

Therefore, the power used by the person is 17 W.

Answer:

Distance s  = 90 meter

Explanation:

Given:

Initial velocity u = 0 m/s

Final velocity v = 30 m/s

Acceleration a = 5 m/s²

Find:

Distance s

Computation:

v² = u² + 2as

30² = 0² + 2(5)(s)

Distance s  = 90 meter

Given :

Mass, m = 68.05 kg.

To Find :

How much gravitational force would you experience on mars ?

Solution :

Acceleration due to gravity on mars is, g = 3.711 m/s²

( You can find it on internet )

Now, weight can be given as :

W = mg

W = 68.05 kg × 3.711 m/s²

W = 252.533 kg m/s² = 252.533 N

Hence, this is the required solution.

Answer:

[tex]Q'_H=1065kJ/min[/tex]

Explanation:

From the question we are told that

Heat Remove rate Q_o= 750 kJ/min

Power Draw P=5.25

a)Generally the coefficient of performance (COP) of an air conditioner is mathematically given  as

[tex]COP=\frac{Q_o}{P}[/tex]

[tex]COP=\frac{750kJ/min}{5.25kw}[/tex]

Where

[tex]750kJ/min=12.5kJ/sec[/tex]

[tex]COP=\frac{12.5kJ/sec}{5.25kw}[/tex]

[tex]COP=2.38[/tex]

b)Generally the equation for power is mathematically represented as

[tex]P=Q_H-Q_o[/tex]

[tex]P+Q_o=Q_H[/tex]

[tex]Q_H=P+Q_o[/tex]

[tex]Q_H=5.25+12.5[/tex]

[tex]Q_H=17.75kW[/tex]

Generally rate of heat transfer to the outside air is mathematically given as

[tex]Q'_H=17.75*60[/tex]

[tex]Q'_H=1065kJ/min[/tex]

Answer:

the moment of inertia of the wheel is is 6.245 kg.m²

Explanation:

Given;

applied force, f = 22.04 N

radius of the wheel, r = 0.34 m

angular acceleration, a = 1.2 rad/s²

The moment of inertia of the wheel is calculated as;

[tex]I = \frac{\tau}{\alpha } \\\\I = \frac{Fr}{\alpha } \\\\I = \frac{22.04 \ \times \ 0.34 }{1.2} \\\\I = 6.245 \ kg.m^2[/tex]

Therefore, the moment of inertia of the wheel is is 6.245 kg.m²

Answer:

friction

Explanation:

the road is the pathway for the vehicle so the tures create friction to stay sturdie

Answer:

Heredity

Explanation:

Can't change the DNA you inherited the same way you can change eating habits+drug use or avoid stress

Answer:

[tex]\boxed {\boxed {\sf C. \ Heredity}}[/tex]

Explanation:

A risk factor is something that increases the chance of getting a disease. Some are controllable, but some are not.

Stress, eating habits, drug use, exercise, smoking, hygiene, and amount of sleep are all controllable or changeable risk factors. Anybody can change these things in their life.

On the other hand, uncontrollable risk factors, such as age, gender, ethnicity and heredity cannot be changed. Nobody has control over these factors.

So, heredity is the uncontrollable risk factor.

Answer:

d = 10.2 m

Explanation:

When the car travels up the inclined plane, its kinetic energy will be used to do the work in climbing up. So according to the law of conservation of energy, we can write that:

[tex]Kinetic\ Energy\ of\ the \ Car = Work\ Done\ while\ moving\ up\ the\ plane\\\frac{1}{2}mv^{2} = Fd[/tex]

where,

m = mass of car

v = speed of car at the start of plane = (36 km/h)(1000 m/1 km)(1 h/3600 s)

v = 10 m/s

F = force on the car in direction of inclination = W Sin θ

W = weight of car = mg

θ = Angle of inclinition = 30°

d = distance covered up the ramp = ?

Therefore,

[tex]\frac{1}{2}mv^{2} = mgdSin\theta\\\frac{1}{2}v^{2} = gdSin\theta\\\frac{1}{2}(10\ m/s)^{2} = d(9.81\ m/s^{2}) Sin\ 30^{0}[/tex]

d = 10.2 m

Answer:

[tex]F_4=\frac{4}{b}F_1[/tex]

Explanation:

Centripetal force is the net force acting on a body which makes it move along a curved path. This force is always towards the center of curvature.

The centripetal force is given by:

F = mv² / r

where m is the mass of the body, v is the velocity of the body, r is the radius, F is the centripetal force and v²/r is the centripetal acceleration.

Given that:

[tex]\frac{v_4}{v_1}=2\\\\v_4=2v_1\\\\ Also, radius\ of\ lane\ 4(r_4)=2*radius\ of\ lane\ 1\\\\Let\ r_1\ be\ radius\ of\ lane\ 1,m=mass\ of\ runner\ in\ lane\ 1=mass\ of\ runner\ in\ lane\ 4\ \\and\ v_4=velocity\ of\ runner\ in\ lane\ 4.\ Hence:\\\\r_4=b*r_1=br_1\\\\The\ centripetal\ force\ for\ lane\ 4(F_4)\ is:\\\\F_4=\frac{mv_4^2}{r_4}\\\\ F_4=\frac{m(2v_1)^2}{br_1}\\\\F_4= \frac{4mv_1^2}{br_1} \\\\But\ F_1=\frac{mv_1^2}{r_1}\\\\Hence\ F_4=\frac{4}{b}F_1[/tex]

F4 is equal to 4/b F1. A further explanation is provided below.

According to the question,

The net force of the object in uniform circular motion will be:

→ [tex]F = \frac{mv^2}{r}[/tex]

∴ [tex]F_1 = \frac{m_1 v_1^2}{r_1}[/tex]

  [tex]F_4 = \frac{m_4 v_4^2}{r_4}[/tex]

Now,

→ [tex]\frac{F_1}{F_4} = \frac{m_1}{m_4}\times (\frac{v_1}{v_4} )^2\times \frac{r_4}{r_1}[/tex]

   [tex]\frac{F_1}{F_4} = \frac{1}{4}\times b[/tex]

   [tex]F_1 = \frac{b}{4} F_4[/tex]

   [tex]F_4 = \frac{4}{b} F_1[/tex]

Thus the above response i.e., "option b" is correct.

Learn more:

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Answer:

T = 3.14 10⁻²  s

Explanation:

The general equation for a traveling transverse wave is

           y = A sin (k x - wt +Ф)

where w is the angular velocity that is related to the period and Ф is the phase of the oscillation

           w = 2π / T          (1)

In this case they indicate that the expression of the wave

         y = 0.003 cos (20 x + 200t)

if we use the relationship of the double angles

          a = kx - wt

          b = Ф

          sin (a + b) = sin a cos b + sin b cos a

for the case Ф = 90 we have

          sin (a + b) = cos b

we substitute

          y = A cos (kx -wt)

with an initial phase of fi = 90º

if we compare the terms of the two expressions

         A = 0.003 m  

         k = 20 m⁻¹

         w = -200  rad/s

the negative sign indicates that the wave goes to the left

if we clear from equation 1

          T = 2π / w

          T = 2π / 200

          T = 3.14 10⁻²  s

Answer:

10.44 liters of gasoline.

Explanation:

First, we need to convert the units of the car from mi/gal to km/L as follows:

[tex] mileage = 32.0 \frac{mi}{gal}*\frac{1.609 km}{1 mi}*\frac{1 gal}{3.785 L} = 13.60 km/L [/tex]

That means that for every liter of gasoline the car travels 13.60 kilometers.

So, to complete a 142-km trip in Europe the volume of gasoline needed is:

[tex] V = \frac{1 L}{13.60 km}*142 km = 10.44 L [/tex]

Therefore, to complete a 142-km trip in Europe we need to buy 10.44 liters of gasoline.

I hope it helps you!                

Answer:

Explanation:

From the given information:

The gravitational potential energy at A is:

[tex]PE_A = mgh[/tex]

GIven that:

mass(m) = 3

height (h) = 3

[tex]PE_A =3\times 9.81 \times 3[/tex]

[tex]\mathbf {PE_A =88.29 \ J }[/tex]

b)

Using the conservation of mechanical  energy:

[tex]PE_A+KE_A = PE_B + KE_B[/tex]

[tex]88.29 +0 = 3(9.8)(1) + KE_B[/tex]

[tex]88.29 = 29.4 + KE_B[/tex]

[tex]KE_B = 88.29 -29.4[/tex]

[tex]\mathbf{ KE_B= 58.89 \ J}[/tex]

From the data provided and the calculations done, the potential energy at A is 88.3 J while the kinetic energy at B is 58.9 J.

The potential energy of a body is given as:

where:

m = mass of the object

g = acceleration due to gravity

h = h

At A:

m= 3.0 kg

g = 9.8 m/s^2

h = 3.0 m

PE = 3 × 9.8 × 3

PE = 88.3 J

Kinetic energy, KE of a body is given as:

where:

From the law of conservation of energy, the sum of potential energy and Kinetic energy at every point is equal.

PE + KE at A = PE + KE at B

KE at B = PE + KE at A - PE at B

At A, PE = 88.3 J and KE = 0

At B; h = 1.0 m

PE = 3 × 9.8 × 1

PE = 29.4 J

Therefore, KE at B = 88.3 + 0 - 29.4

KE at B = 58.9 J

Therefore, the potential energy at A is 88.3 J while the kinetic energy at B is 58.9 J.

Learn more about potential energy and Kinetic energy at: https://brainly.com/question/14427111

Answer:

σ = ±708 nC/m²

Q = ±177 nC

Explanation:

given data

Side of copper plate L = 50 cm

Electric field, E = 80 kN/C

solution

we get here Charge density,σ that is express as

σ = E x ε₀         ....................1

here ε₀ is Permittivity of free space that is 8.85 x 10⁻¹² C²/Nm²

so put value in eq1we get

σ = 80 x 10³ x 8.85 x 10⁻¹²

σ = 708 x 10⁻⁹ C/m²

σ = 708 nC/m²

and

now we get here total change on each faces

Q = σ  A    ...............2

Q = 708 x 10⁻⁹ x (0.50)²

Q = 177 nC

Answer:

the heat emitted by potatoes is much less than the heat emitted by turkey

Explanation:

The heat transfer is given by

        Q = m [tex]c_{e}[/tex] ΔT

where m is the mass of the body, c_e is the specific heat and ΔT is the change in temperature of the body

in this case they ask us to appear the heat emitted by the potatoes and the turkey.

From the tables found the specious colors of both

potato     c_e = 0.82 Kcal / kg ºC

turkey      c_e = 0.72 Kcal / kg ºC

Since the two bodies have the same initial temperature and we assume that they reach the same final (ambient) temperature, the ratio of the heat emitted is

          Q₁ / Q₂ =  [tex]\frac{ m_1 \ c_{e1} }{m_2 \ c_{e2} }[/tex]

where we use the rise 1 for the potatoes and the su index 2 for the turkey

the mass of the potatoes can be estimated at approximately m = 1 ka

we substitute

          Q₁ / Q₂ =  [tex]\frac{1 \ 0.82}{ 20 0.72}[/tex]

           Q₁ /Q₂ = 0.0569

           Q₁ = 0.0569 Q₂

therefore the heat emitted by potatoes is much less than the heat emitted by turkey

Answer:

a= 17.69 m/s^2

Explanation:

Step one:

given data

A car accelerates uniformly from rest to 23 m/s

u= 0m/s

v= 23m/s

distance= 30m

Step two:

We know that

acceleration= velocity/time

also,

velocity= distance/time

23= 30/t

t= 30/23

t= 1.30 seconds

hence

acceleration= 23/1.30

accelaration= 17.69 m/s^2

Answer:

C increase in potential energy

Answer:

B - the box pushing against the boy

Explanation:

Newton's third law of motion also known as the law of action and reaction  states that for every action there is equal and opposite reaction.

The action force is the force acting in one direction while the reaction force is  the force acting in the opposite direction. for example, when a person wants to jump, the person exerts a downward force on the ground known as action force and also, the ground exerts upward force on the person known as reaction force.

If the action force is the boy pushing the box, what is the reaction force is the box pushing against the boy.

Answer:

5.67

Explanation:

force is = m x a

which will give us

0.63

x 9

= 5.67