Answer:
C. Increase in back emf
Explanation:
As the current through the field winding decreases the field strength also decreases and the back-emf is reduced, as a result the motor speeds up.
When the motor begins to speed-up, an additional back EMF is generated due to induction which reduces armature current. This also results in reduced strength of the field flux. The back emf generated is not enough to reduce the armature current which could stop the acceleration of the motor and the motor further accelerates.
the bodies in this universe attract one another name the scientist who propounded this statement
Answer:
It was proposed by Isaac Newton
Explanation:
The law of universal attraction of expression
F = [tex]G \ \frac{m_1m_2}{ r^2}[/tex]G m1m2 / r ^ 2
where G is a constant, m₁ and m₂ are the masses of the bodies and r the distance between them.
It was proposed by Isaac Newton
With this law Newton explained that the force that pulls the moon towards the earth is the same as that which attracts an apple towards the earth
train starting from a railway station and moving with a uniform accleration attains a speed of 90km/hr in 10s .Find the accleration
Options
90m/s2
1m/s2
10m/s2
0.1m/s2
Answer:
a= 2.5m/s²
Explanation:
U=0
V=90km/hr
T= 10s
Convert 90km/hr to m/s
1km= 1000m
1hr= 3600s
(60×60)
therefore, 90km/hr = 90000/3600
90km/hr= 25m/s
From Newton First Equation,
V=U + AT
25=0+ A(10)
25= 10A
25/10 =10A/10
A= 2.5m/s²
Unlike hard disks, which use magnetic charges to represent 1s and 0s, _____ use reflected light.
Answer:
Unlike hard disks, which use magnetic charges to represent 1s and 0s, Compact Disks, DVD's or Blue Rays use reflected light.
Explanation:
The way CD's work is that they are hit by a laser beam which is reflected on the surface of the disc. These disks have some valleys and mountains that reflect light differently so the CD player will interpret these differences in reflection as data which will then be turned into music, videos or computer files.
Ali while driving to school computes the average speed for his trip to be 20km/hr on his return trip along the same route. There is less traffic and average speed is 30km/hr. What is the average speed for Ali's trip?
Answer:
25 km/hr
Explanation:
Since Ali's average speed for his trip to school is u = 20 km/hr and his average speed for the return trip to back home from school is v = 30 km/hr, thus his total average speed for the journey is thus V = (initial average speed + final average speed)/2 = (u + v)/2
Substituting the values of the variables into the equation, we have
V = (u + v)/2
V = (20 km/hr + 30 km/hr)/2
V = 50 km/hr/2
V = 25 km/hr
So, the average speed for Ali's trip is 25 km/hr
at which point is the Kinetic energy the lowest?
Answer:
the lowest kinetic energy point is option D
¿Cuántos electrones por segundo pasan a través de una sección de alambre que lleva una corriente de 0.70 A.?
Answer:
The number of electrons flowing per second is [tex]4.375\times 10^{18}[/tex].
Explanation:
How many electrons per second pass through a section of wire that carries a current of 0.70 A.?
Current, I = 0.7 A
time, t = 1 s
According to the definition of current, let the charge is q.
q = I t
q = 0.7 x 1 = 0.7 C
Let the number of electrons is n.
[tex]n =\frac{q}{e}\\\\n = \frac{0.7}{1.6\times 10^{-19}}\\\\n = 4.375\times 10^{18}[/tex]
If an object is thrown in an upward direction from the top of a building 160 ft high at an initial speed of 30 mi/h, what is
its final speed when it hits the ground? (Disregard wind resistance. Do not reflect negative direction in your answer.)
ft/s
110 fus
100 ft/s
097 ft/s
91 ft/s
NEXT QUESTION
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Answer:
We can use 2 g H = v2^2 - v1^2 or
v2^2 = 2 g H + v1^2
Since 88 ft/sec = 60mph we have 30 mph = 44 ft/sec
The object will return with the same speed that it had initially so the object
starts out with a downward speed of 44 ft/sec
Then v2^2 = 2 * 32 ft/sec^2 * 160 ft + 44 (ft/sec)^2
v2^2 = (2 * 32 * 160 + 44^2) ft^2 / sec^2 = 12180 ft^2/sec^2
v2 = 110 ft/sec
_______ is an optical filter that passes light of a specific polarization and blocks waves of other polarizations.
a. Index of refraction
b. Laser
c. Polarizer
This filter picks out a specific polarization, so it makes a lot more sense to call it a polarizer than anything else. (C)
This question is a lot like asking "What color is an orange ?".
when you order clothes, does the sweater has to be longer than your shirt to fit you just like the shirt?
Answer:
Yes.⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀⠀
Which of the following supports the theory of continental drift?
A. Mountains on different continents match up.
B. Earth's crust is all in one piece.
C. Earth has hot climates at the equator.
D. There is one continent on Earth.
Answer:
A. Mountains on different continents match up.
Explanation:
Due to the drifting/ moving apart of the continents, land masses is split therefore in case of a mountain that split, it matches the other part in another continent.
4. Which of the following statement describes the particle model.
A. The average kinetic energy of the particles changes easily
B. All matter is made up of large triangular particles
C. There are no spaces between the particles
D. The average kinetic energy of all the particles remains constant
E.Other:
A boy travels 12km east wards to a point B and then 5km southwards to another point C. Calculate the difference between the magnitude of the displacement of the boy and the distance travelled by him
The difference b/w the displacement and total distance traveled is 4km.
Explanation.
▪ total distance - displacement
= 17 km - 13 km
= 4 km...answer
You can see stars brighter than magnitude +6 with your naked eye under dark sky conditions, and you can also see the full moon at magnitude –13. (You can glance at the Sun, which is at magnitude –27, but you can't safely look at the Sun.) Given these limits, what is the dynamic range of the naked eye?
asset question.....only answers otherwise u will be reported
Answer:
C. 24 hrs
Explanation:
it takes the earth 24 hrs to make one full revolution.
How much current flows in the circuit if two resistors of 6 connected in parallel are
supplied with potential difference of 12 volts?
Answer:
4 A
Explanation:
Firstly we need to calculate the equivalent resistance. Since, two resistors of 6 connected in parallel, so equivalent resistance will be given by,
[tex]\longrightarrow[/tex] 1/R = 1/R1 + 1/R2
[tex]\longrightarrow[/tex] 1/R = (1/6 + 1/6) Ω
[tex]\longrightarrow[/tex] 1/R = (1 + 1)/6 Ω
[tex]\longrightarrow[/tex] 1/R = 2/6 Ω
[tex]\longrightarrow[/tex] R = 6/2 Ω
[tex]\longrightarrow[/tex] R = 3 Ω
We know that,
[tex]\longrightarrow[/tex] V = IR
V denotes p.d (12V)I denotes currentR denotes resistance (3 Ω)[tex]\longrightarrow[/tex] 12 = I × 3
[tex]\longrightarrow[/tex] 12 ÷ 3 = I
[tex]\longrightarrow[/tex] 4 Ampere = I
6. An object is fired from the gound at 275 m/s at an angle of 55° N of E.
a. How far away did the object first hit the ground?
b. what is the maximum height that the object reaches?
there u go fella hope u understood
What happens to the electric force between two particles if the distance
between them is doubled?
A. It decreases to half the original force.
B. It increases to twice the original force.
C. It increases to 4 times the original force.
D. It decreases to 1/4 of the original force.
Answer:
D.
Explanation:
Force and distance are inversely related, so a greater distance results in a weaker force.
ive an example of a pair of variables that have negative correlation. A. The quantity of fertilizers used and crop yield. B. The color of a person's shirt and the number of meals sold at Chinese restaurants. C. The number of physicists and the speed of sound. D. The number of winter coats sold and the temperature outside.
Answer:
D. The number of winter coats sold and the temperature outside.
Explanation:
A negative correlation can be described as a relationship existing between two variables such that as one of these variables goes up, the other variable would go down and vice versa.
With this explanation in mind, as the temperature outside increases, less winter coats would be sold because an increase in temperature would mean more heat and hotness. People would be uncomfortable wearing thick clothing.
Quickly pls!!! A wave with a wavelength of 0.5 m moves with a speed of 1.5 m/s. What is the frequency of the wave?
A. 2.0 Hz
B. 1.0 Hz
C. 0.33 Hz
D. 3.0 Hz
¿ Sobre que superficie se desplazara mas rápidamente un tejo, sobre cemento o sobre cerámica? ¿por que?
Answer:
cemento potque es plano
A wave travels at 330m/s^-1. the wavelength is found to be 2.4m.
Calculate the period of oscillation of a article in the medium transmitting the waves.
The frequency of oscillations of the source transmitting the wave
Answer: frequency 137.5
Time period 0.01sec
Explanation:
A 72 kg swimmer dives horizontally off a raft floating in a lake. The diver's speed immediately after leaving the raft is 3.8 m/s. If the time interval of the interaction between the diver and the raft is 0.25 s, what is the magnitude of the average horizontal force by diver on the raft?
Answer:
F = 1094.4 N
Explanation:
From impulse - momentum theorem, we now that ;
Impulse = momentum
Where;
Formula for impulse = force (F) × time(t)
Momentum = mass(m) × velocity(v)
Now, we are given;
Mass of swimmer; m = 72 kg
Speed; v = 3.8 m/s
Time; t = 0.25 s
Thus;
F × t = mv
F = mv/t
F = (72 × 3.8)/0.25
F = 1094.4 N
This value of force is the magnitude of the average horizontal force by diver on the raft.
(e) Find the height and orbital velocity of the geostationary satellite above the earth assuming earth as a sphere of radius 6370 km. [Radius of earth, R = 6370km, Acceleration due to gravity
= 10ms)
Answer:
I don't really know this one trust me am not lieing
An unstrained horizontal spring has a length of 0.40 m and a spring constant of 340 N/m. Two small charged objects are attached to this spring, one at each end. The charges on the objects have equal magnitudes. Because of these charges, the spring stretches by 0.033 m relative to its unstrained length. Determine (a) the possible algebraic signs and (b) the magnitude of the charges.
Answer:
(a) Both the charges are positive or negative.
(b) Teh value of each charge is 1.53 x 10^-5 C.
Explanation:
Spring constant, K = 340 N/m
Natural length, L = 0.4 m
stretch, y = 0.033 m
(a) Let the charge on each sphere is q and they repel each other so the nature of charge of either sphere may be both positive or both negative.
(b) The electrostatic force is balanced by the spring force.
[tex]\frac{kq^2}{(L + y)^2}=Ky\\\\\\\frac{9\times 10^9 q^2}{(0.4 +0.033)^2} = 340\times0.033\\\\q= 1.53\times 10^{-5} C[/tex]
An airplane flies eastward and always accelerates at a constant rate. At one position along its path, it has a velocity of 32.7 m/s . It then flies a further distance of 48500 m , and afterwards, its velocity is 44.7 m/s . Find the airplane's acceleration.
Answer:
[tex]\quad[/tex]0.0095 m/s²
Explanation:
We have,
Initial velocity (u) = 32.7 m/sFinal velocity (v) = 44.7 m/sDistance travelled (s) = 48500 mWe are asked to calculate the airplane's acceleration.
By using the third equation of motion,
➝ v² - u² = 2as
v denotes final velocityu denotes initial velocitya denotes accelerations denotes distance➝ (44.7)² - (32.7)² = 2 × a × 48500
➝ 1998.09 - 1069.29 = 97000 × a
➝ 928.8 = 97000a
➝ 928.8 ÷ 97000 = a
➝ 0.0095 m/s² = a
Determine the amount of potential energy of a 4.2 kg book that is placed on a shelf with a height of 0.9 meters. Round your answer to one decimal place
Answer:
that is a correct answer maybe .
please help me with this question
Answer:
(4) A = 3 A, A₂ = 11 A
(5) 7 A
Explanation:
(4)
From the diagram,
A = 3+6+2
A = 11 A
V = A₂R
A₂ = V/R₂............ Equation 1
Given: V = 12 V, R₂ = 4 Ω
Substitute these values into equation 1
A₂ = 12/4
A₂ = 3 A
(5) Applying,
V = IR'
I = V/R'............ Equation 1
Where V = Voltage, I = cuurent, R' = total resistance.
But,
1/R' = (1/3)+(1/4)
1/R' = (3+4)/12
1/R' = 7/12
R' = 12/7 Ω
Given: V = 12 V
Substitute these values into equation 1
I = 12/(12/7)
I = 7 A
Therefore
A = 7 A
This question is divided into two parts. This is part (a) of the question. A proton accelerates from rest in a uniform electric field of 580 N/C. At some later time, its speed is 1.00 x 106 m/s. (a) Find the magnitude of the acceleration of the proton. (Mass of the proton is 1.67 x 10-27 kg and charge is 1.60 x 10-19 C) (in the following options 10^10 m/s^2 is 1010 m/s2)
Answer:
The acceleration of proton is 5.56 x 10^10 m/s^2 .
Explanation:
initial velocity, u = 0
Electric field, E = 580 N/C
final speed, v = 10^6 m/s
(a) Let the acceleration is a.
According to the Newton's second law
F = m a = q E
where, q is the charge of proton and m is the mass.
[tex]a= \frac{q E}{m}\\\\a = \frac{1.6\times10^{-19}\times 580}{1.67\times 10^{-27}}\\\\a= 5.56\times 10^{10} m/s^2[/tex]
Mike is serving the volleyball for the second time in a volleyball game. If the ball leaves his hand with twice the velocity it had on the first serve, its horizontal range R would be:
Answer:
His new horizontal range is 4 times his initial range.
Explanation:
Since Mike serves the ball with velocity, u, his horizontal range is
R = u²sin2Ф/g where Ф is the angle between u and the horizontal.
Now, if on his second serve, the ball leaves his hand with twice the velocity of his initial serve, the new velocity is v = 2u.
So, the new range R' = v²sin2Ф/g
R' = (2u)²sin2Ф/g
R' = 4u²sin2Ф/g
Since R = u²sin2Ф/g,
R' = 4u²sin2Ф/g
R' = 4R
So, his new horizontal range is 4 times his initial range.
show that pv=nrt has the same unit with energy
Answer:
The unit of the equation P·V = n·R·T is the Joules which is the same as the unit of energy
Explanation:
The unit of energy is Joules, with symbol J
The given equation for an ideal gas is P·V = n·R·T
Where;
P = The pressure of the gas with units Pascals, Pa
V = The volume of the gas, with units m³
n = The number of moles with unit moles
R = The universal gas constant = 8.314 J/(mol·K)
T = The temperature, with units, Kelvin, K
Therefore, we get;
P·V has unit 1 Pa × 1 m³ = 1 N/m² × 1 m³ = 1 N·m = 1 Joule
Similarly, we get
n·R·T with units n mole × 8.314 J/(mol·K) × 1 K = 8.314·n Joules
Therefore, P·V = n·R·T, has the unit of Joules which is the same unit with energy.
