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.
Write a short note on Contribution of Isaac Newton to Physics
Answer:
In Principia, Newton formulated the laws of motion and universal gravitation that formed the dominant scientific viewpoint until it was superseded by the theory of relativity.
A pair of forces with equal magnitude, opposite directions, and different lines of action is called a "couple." When a couple acts on a rigid object, the couple produces a torque that does not depend on the location of the axis. The drawing shows a couple acting on a tire wrench, each force being perpendicular to the wrench. Determine an expression for the torque produced by the couple when the axis is perpendicular to the tire and passes through the following. Express your answers in terms of the magnitude F of the force and the length L of the wrench.
The drawing shows the couple acting on a tire wrench is missing and so i have attached it.
We are to find an expression for the torque when the axis is perpendicular to the tire and passes through the points A, B & C
Answer:
Point A: τ = Fl
Point B: τ = 0
Point C: - Fl
Explanation:
Formula for torque is;
τ = F × d
Where;
F is perpendicular force
d is distance.
Thus;
> At point A, it means we are taking torque about point A and so we have;
τ = (-F × 0) + (F × L)
τ = Fl
> At point B, it means we are taking torque about point B and so we have;
τ = (-F × L/2) + (F × L/2)
τ = -(FL/2) + (FL/2)
τ = 0
> At point C, it means we are taking torque about point C and so we have;
τ = (-F × L) + (F × 0)
τ = -FL
where would the spaceprobe experience the strongest net (or total) gravitional force exerted on it by Earth and Mars
Answer:
r = 41.1 10⁹ m
Explanation:
For this exercise we use the equilibrium condition, that is, we look for the point where the forces are equal
∑ F = 0
F (Earth- probe) - F (Mars- probe) = 0
F (Earth- probe) = F (Mars- probe)
Let's use the equation of universal grace, let's measure the distance from the earth, to have a reference system
the distance from Earth to the probe is R (Earth-probe) = r
the distance from Mars to the probe is R (Mars -probe) = D - r
where D is the distance between Earth and Mars
[tex]G \ \frac{m \ M_{Earth}}{r^2} = G \ \frac{m \ M_{Mars}}{(D-r)^2}[/tex]
M_earth (D-r)² = M_Mars r²
(D-r) = [tex]\sqrt{ \frac{M_{Mars}}{ M_{Earth}} }[/tex] r
r ( [tex]1 + \sqrt{ \frac{M_{Mars}}{M_{Earth}} }[/tex]) = D
r = [tex]\frac{D}{ 1+ \sqrt{\frac{M_{Mars}}{ M_{Earth}} } }[/tex]
We look for the values in tables
D = 54.6 10⁹ m (minimum)
M_earth = 5.98 10²⁴ kg
M_Marte = 6.42 10²³ kg = 0.642 10²⁴ kg
let's calculate
r = 54.6 10⁹ / (1 + √(0.642/5.98) )
r = 41.1 10⁹ m
[tex]explain \: \\ \\ how \: rainbow \: form \: {?}[/tex]
¿Qué diferencia una magnitud fundamental de una derivada?
Answer:
Explanation:
Una magnitud fundamental es aquella que se define por si misma y es independiente de las demás (masa, tiempo, longitud, etc.). magnitud derivada. Una magnitud derivada es aquella que se obtiene mediante expresiones matemáticas a partir de las magnitudes fundamentales (densidad, superficie, velocidad).
How does work affect energy between objects so it can cause a change in the form of energy?
A. Work transfers energy.
B. Work changes energy.
C. Work increases energy.
D. Work decreases energy.
How did the current change when the circuit was initially closed in Part 2 of this exercise? Explain your answer by referencing Panel 1 and the definitions of a capacitor and of current.
Answer:
Some current is lost.
Explanation:
Change occur in the current when the circuit was initially closed because in a closed circuit the current moves from the start towards the end of the circuit through various resistors. There is heat produced in the wire when the current flows through the circuit. Due to this heat, some of the current is lost during on his own way. Capacitor is a device used to store an electric charge, having of one or more pairs of conductors separated by an insulator. while on the other hand, electric current is a stream of charged particles, such as electrons moving through conductor or space.
E
How does the construction of dams positively affect natural resources?
by providing water for irrigation and restoring trees to areas where forests once existed
by creating reservoirs, preventing flooding, and renewing destroyed ecosystems
by preventing flooding, creating reservoirs, and providing water for irrigation
by renewing destroyed ecosystems and restoring trees to areas where forest once ersted
Answer:
by preventing flooding, creating reservoirs, and providing water for irrigation
Dams and waterways store and provide water for irrigation so farmers can use the water for growing crops. This idea goes way back into history. Irrigation is an important part of using water. In areas where water and rain are not abundant (like the desert), irrigation canals from rivers and dams are used to carry water.
Dams help in preventing floods. They catch extra water so that it doesn’t run wild downstream. Dam operators can let water out through the dam when needed.
The material that would eventually make all the major bodies in our solar system first gathered together as smaller pieces which astronomers call:
Answer:
The answer is "planetesimals".
Explanation:
The uncountable little corpses of the accreted gas and dust were supposed to orbit the Sun while the planets were formed. The theory explaining the creation of the solar system as a whole is termed the quark-gluon plasma hypothesis.
An object produced by dust, rock, and other materials is called a planetesimal. This word is rooted throughout the microscopic idea, which shows that an object is too small to observe or quantify. Everywhere from many meters to hundreds of kilometers asteroids may acquire size.
a trampoline launches a 50kg person 2m into the air. if the springs push with 1960N of force, how much displacement was there in the trampoline
Answer: 0.5 m
Explanation:
Given
Mass of the person is [tex]m=50\ kg[/tex]
Trampoline launches the person into the air up to height of [tex]h=2\ m[/tex]
Force experience by springs is [tex]F=1960\ N[/tex]
Here, the work done on displacing the springs is equivalent to the Potential energy acquired by the person i.e.
[tex]\Rightarrow F\cdot x=mgh\quad [\text{x=displacement of the trampoline}]\\\\\text{Insert the values}\\\\\Rightarrow x=\dfrac{50\times 9.8\times 2}{1960}\\\\\Rightarrow x=\dfrac{980}{1960}\\\\\Rightarrow x=0.5\ m[/tex]
Answer:
0.5
Explanation:
A gas is enclosed in a confainer fitted with a piston of cross sectional area 0.10 the pressureof the gas is maintained in 8000 when hat is slowlh transferred the piston is pushed up through a distance of 4.0cm If 42j of heat is transferred to the system during expansion wht is the change im internal energy of th system
Answer:
10 Joule
Explanation:
The solution and answer are well written in the Pic above.
For taking bath, water at 40⁰C is required. Calculate the mass of cold water at 15⁰C which is to be added in 60 Kg water at 100⁰C for bathing purpose. 1 point a) 51Kg b) 47Kg c) 44 Kg d) 39Kg
(d)
The signals for the monitor unit are transmitted as electromagnetic waves with a
wavelength of 0.125 m.
Wave speed of electromagnetic waves = 3 * 108 m/s
Calculate the frequency of the signal.
Answer:
Frequency = 24 × 10⁸ Hz
Explanation:
Given the following data;
Speed = 3 × 10⁸ m/s
Wavelength = 0.125 meters
To find the frequency of the electromagnetic wave;
Mathematically, the speed of a wave is given by the formula;
Speed = Wavelength × frequency
Substituting into the formula, we have;
3 × 10⁸ = 0.125 × frequency
Frequency = (3 × 10⁸)/0.125
Frequency = 24 × 10⁸ Hz
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Ariana is accelerating her car at a rate of 4.6 m/s2 for 10 seconds. Her starting velocity was 0 m/s.
What was her final velocity?
0 m/s
2.3 m/s
4.6 m/s
46 m/s
Answer:
46
Explanation:
v = at so 4.6 x 10 = 46
A thin rod of length 1.4 m and mass 180 g is suspended freely from one end. It is pulled to one side and then allowed to swing like a pendulum, passing through its lowest position with angular speed 1.80 rad/s. Neglecting friction and air resistance, find (a) the rod's kinetic energy at its lowest position and (b) how far above that position the center of mass rises.
Answer:
[tex]K.E = 0.1905 J[/tex]
Explanation:
From the question we are told that:
Length [tex]L=1.4m[/tex]
Mass [tex]m=180g[/tex]
Angular Velocity [tex]\omega=1.80rads/s[/tex]
Generally the equation for Kinetic energy K.E is mathematically given by
[tex]K.E =0.5 (1/3 ML^2 )w^2[/tex]
[tex]K.E =0.5 ( 1/3 * 0.18 * 1.4^2 ) 1.8^2[/tex]
[tex]K.E = 0.1905 J[/tex]
3.00 m^3 of water is at 20.0°C.
If you raise its temperature to
60.0°C, by how much will its
volume expand?
Water
ß = 207•10-6C-1
(Unit = m^3)
Answer:
9m^3
Explanation:
Given data
volume v1= 3m^3
volume v2= ???
Temperature T1= 20.0°C.
Temperature T2= 60.0°C.
Applying the relation for temperature and volume
V1/T1= V2/T2
substitute
3/20= V2/60
3*60= V2*20
180= 20*V2
180/20= V2
V2= 9m^3
Hence the final volume is 9m^3
a wave in which particles of the medium vibrate at right angles to the direction that the wave travels is called?
Explanation:
Longitudinal waves are waves in which the vibration of the medium is parallel to the direction the wave travels and displacement of the medium is in the same (or opposite) direction of the wave propagation. Mechanical longitudinal waves are also called compressional or compression waves, because they produce compression and rarefaction when traveling through a medium, and pressure waves, because they produce increases and decreases in pressure.
Answer:
In transverse waves, particles of the medium vibrate to and from in a direction perpendicular to the direction of energy transport.
Explanation:
hope it will help u
The 75.0 kg hero of a movie is pulled upward at a constant velocity by a rope. What is the tension on the rope?
Answer:
750 N
Explanation:
the tension on the rope is the weight of the hero
What is photosynthesis???
photosynthesis, the process by which green plants and certain other organisms transform light energy into chemical energy. During photosynthesis in green plants, light energy is captured and used to convert water, carbon dioxide, and minerals into oxygen and energy-rich organic compounds.[tex]\pmb{ }[/tex]
TRUE OR FALSE. when an object changed direction without changing its speed, it is not accelerating
Answer:
True.
Explanation:
The velocity vector is constant in magnitude but changing in direction. Because the speed is constant for such a motion, many students have the misconception that there is no acceleration. ... But the fact is that an accelerating object is an object that is changing its velocity.
What is an electric fuse? What is the working principle of electric fuse?
7. Explain how sound waves striking the tympanic membrane result in movement of fluids in the inner ear.
Answer:
This has been explained below.
Explanation:
Sound waves move along the auditory canal and when moving they hit the tympanic membrane making it to vibrate. this vibration would make the 3 ossicles to move. the tympanic membrane is sticked to the auditory ossicles and the stapes are joined to the oval window. as movements occur in the oval window, there would be motions happening in the cochlea
HOW OLD IS THE ISS? HOW LONG HAS IT BEEN OPERATIONAL?
Answer:
bhai nam kya hai (whats your name)
Explanation:
please comment
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26. D. crushing the sugar cube and dissolving it in water.
27. A. atom
28. B. molecule
29. B. plum pudding model of Joseph John Thomson
30. B. He used cathode ray tubes which showed that all atoms contain tiny negatively charged subatomic particles or electrons.
31. D. protons and neutrons are relatively heavier than electrons.
If 6000 J of heat is added to 200 gm of water at 25° C. What will be its final
temperature?
Answer:
T₂ = 305.17 K
Explanation:
Given that,
Heat, Q = 6000 J
Mass, m = 200 gram
Initial temperature, T₁ = 25° C
We need to find its final temperature. Let it is T₂.
We know that,
[tex]Q=mc\Delta T[/tex]
Where
c is the specific heat of water, c = 4.18 J/g°C
So,
[tex]6000=200\times 4.18\times (T_2-298)\\\\\dfrac{6000}{200\times 4.18}=(T_2-298)\\\\7.17=(T_2-298)\\\\7.17+298=T_2\\\\T_2=305.17\ K[/tex]
So, the final temperature is equal to 305.17 K.
How does sound travel?
In Boolean Algebra 1 represent
a)5V
b)1V
c)Both a&b
d)None of above
Answer:
hey hi mate
ur answer is move of above
hope you like it
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Glass lenses are practically opaque to an emission source with the wavelength shorter than 400nm. (True or False)
Answer:
the statement is TRUE
Explanation:
Most lenses are made of glass that has a strong absorption below 400 nm,
Only special evaporation lenses are made of quartz and fused silica which has a high absorption below 200 nm.
therefore the statement is TRUE
If the universe is infinite, then how come there are things disappearing from the horizon? I was at a point in this video (TRUE Limits Of Humanity from Kurzgesagt) about true limits of humanity, and the narrator mentioned that (04:12) "...there is a cosmological horizon around us. Everything beyond it, is traveling faster, relative to us, than the speed of light. So everything that passes the horizon is irretrievably out of reach forever and we will never be able to interact with it again." Are they talking about how galaxies passing the horizon are physically absent, or just visually aren't there and we are unable to interact with them?
Answer:
The big rip theory
Explanation:
I believe what you are referring to is the big rip theory, in which the universe expands faster than the speed of light Kurzgesagt refers to it as a "horizon" but in reality it's a little more complicated than that. Eventually the expansion of the universe will accelerate far beyond the speed of light creating space between molecules until eventually all matter is fleeting and the entire universe is an endlessly vast cosmic void with not but the occasion molecule left from a time when things weren't so lonely.
How did the English bill of rights impact the colonists views of government?
The English Bill of Rights helped to shape the colonists' views of government by promoting the ideas of individual liberty, representative democracy, and limited government.
What is English bill of rights?The English Bill of Rights is a document that was passed by the Parliament of England in 1689. It was a key moment in the development of modern democratic government, as it established certain rights and protections for English citizens, such as the right to bear arms, the right to a fair trial, and the prohibition of cruel and unusual punishment.
The English Bill of Rights also limited the power of the monarchy, requiring the king or queen to obtain the consent of Parliament before levying taxes or making other important decisions. Its influence can still be seen today in many democracies around the world.
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