28 Why is soft iron used for the core of an electromagnet?
А Soft iron easily becomes a permanent magnet.
B Soft iron is a good electrical conductor.
с Soft iron is a poor thermal conductor.
D Soft iron loses its magnetism when the current in the coil is switched off.
Answer:
An electromagnet is a form of magnet that is made by the passage of electric current through a coil of wire. The core of an electromagnet increases the strength of the produced magnetic field
Soft iron is used as the core of an electromagnet because soft iron is a magnetic material and therefore it is permeable to and becomes magnetized by the magnetic field coming from the flowing current, thereby allowing more flux to pass through the core of the electromagnet, producing a magnetic field strength that is several times that of an air core electromagnet as the relative permeability (to magnetic flux, compared to vacuum) of soft iron is about 64 × 10³
However, once the current is switched, the soft iron does not remain its magnetic, and therefore, the electromagnet becomes demagnetized, thereby being able to maintain its electromagnetic characteristics (being made magnetic by the flow of electric current)
Explanation:
Define the term ‘matter’ in physics.
Answer:
Matter is any substance that has mass and takes up space by having volume
A car is traveling at 36km/h when it accelerates and after 2 seconds the car reaches a speed of 54km/h. Calculate the speed of the car in 2s?
define Neutons 3rd law .
Answer:
that when two object interact, they apply forces to one another that are equal in magnitude and opposite in direction.
Explanation:
Newton's third law: the law of action and reaction
In a simple machine the energy input is 120J if the efficiency of the machine is 80% calculate the energy output
Answer:
E_O = 96J
Explanation:
E_O = E_I*(%e/100%)
E_O = 120J*(80%/100%)
E_O = 96J
If the force on a spring is 2 N and it stretched 0.5 m, what is the spring constant?
O A. 2 N/m
OB. 0.2 N/m
OC. 0.4 N/m
OD. 4 N/m
answer is
0.4n/mThe hair dryer has a plastic case so there is no need for an earth wire connection in the plug ,explain why the hair dryer is still safe to use.
Answer:
plastics are unable to conduct electricity and heat due to there being no free flowing electrons, meaning they are safe to use.
Explanation:
a car moves at a speed of 40km/h. it is stopped by applying brake which produce a uniform acceleration of-0.5m/s^2. how much distance will it move before coming to stop ? plz its urgent
Answer:
Explanation:
I answered this in question #24313516
A converging lens of focal length 20cm, forms a real image twice the size of the object. Calculate:
i) the power of the lens;
ii) the position of the image.
Answer:
Solition given:
focal length(f)=20cm
size of image(v)=2x
size of object(u)=x
we have
power of lens= reciprocal to focal length=1/20=0.05/cm
ii.
the position of the image is beyond C.
Explanation:
See the attachment !!!!!!!
A rabbit runs a distance of 60 meters in 20s. What is the average speed?
Answer:
3 m/s
Explanation:
Given,
Total distance = 60 m
Total time = 20 s
We know that,
Average speed = Total distance/Total time
=> Average speed = 60 m/20 s
=> Average speed = 3 m/1 s
=> Average speed = 3 m/s
Average speed=Total distance/Total time
[tex]\\ \sf\longmapsto Average\:Speed=\dfrac{60}{20}[/tex]
[tex]\\ \sf\longmapsto Average\:Speed=3m/s[/tex]
How many atoms are in the compound NaNO3?
Explanation:
3 atoms are in the compound
How does the temperature of a planet determine the states of matter you would observe on that planet?
Explanation:
the temperature will determine the kinetic energy or degree of freedom of the molecules of matter.
if the temperature is high, the kinetic energy of the molecules increase which may cause a change of state into a gas which has molecules of high kinetic energy. this shows that temperature is a measure of the kinetic energy of the molecules.
If we aim a radio telescope at a distant spiral arm of the Milky Way Galaxy, we will probably observe a 21-cm line. If we point a large optical telescope at this same region, we will probably not be able to detect the neutral hydrogen that gives rise to the 21-cm radio signal. Why not
Answer:
Because of the interstellar dust and interior location of the solar system.
Explanation:
We will probably not be able to detect the neutral hydrogen that gives rise to the 21-cm radio signal if we point a large optical telescope to the region because, the interstellar dust obscures the location of the spiral arm of the Milky way galaxy and this makes neutral hydrogen that gives rise to the 21-cm radio signal difficult to detect.
Also, the interior location of the solar system also makes the neutral hydrogen that gives rise to the 21-cm radio signal difficult to detect.
So, the interstellar dust and the interior location of the solar system makes it difficult to detect the neutral hydrogen that gives rise to the 21-cm radio signal with a large optical telescope.
how much would a 70 kg mean weight on the Moon what should be its mass on the earth and on the moon
Answer:
I don't know sorry' please
Describe the laws of liquid pressure and explain the term fluid. (Please try to give the correct answer 'coz it's urgent!)
Answer:
The laws of liquid pressure are: ... The liquid pressure at a point inside the liquid is same in all directions. The liquid pressure at a point inside the liquid is directly proportional to the depth of that point from the free surface of liquid. The pressure of liquid at same depth is different for different liquids
Answer:
The laws of liquid pressure:
The pressure that is inside the liquid rises with the intensity from the surface of a liquid.
The term fluid:
Fluid is basically liquid and a substance that is known to have no certain shape. The opposite of the term fluid would be solid.
A position of a particle moving on an x axis is given by x=7•4 + 9•2t - 2•1 t^3, with x in meters and t in seconds. what is its velocity at t=3•5s? is the velocity,or is it Continuously changing?
Answer:
The velocity at that time would be [tex](-67.975\; \rm s)[/tex]. The velocity of this particle is continuously changing.
Explanation:
Differentiate the expression for position [tex]x[/tex] with respect to time [tex]t[/tex] to find an expression for velocity.
[tex]\begin{aligned}v(t) &= \frac{d}{dt}[x(t)] \\ &= \frac{d}{dt} \left[ 7.4 + 9.2\, t - 2.1\, t^{3}\right]\\ &= 9.2 - 6.3\, t^{2}\end{aligned}[/tex].
Hence, at [tex]t = 3.5\; \rm s[/tex], velocity would be [tex]v(3.5) = 9.2 - 6.3 \times (3.5)^{2} = -67.975\; \rm m[/tex].
Since velocity [tex]v(t)[/tex] changes with time [tex]t[/tex], the velocity of this particle is continuously changing.
Mass of the sun is 2x10³⁰ kg and that of the earth is 6/10²⁴ kg and the distance between them is 1.5 x 10¹¹m. What is the gravitational force produced between them?
Answer:
The gravitational force is 3.56 × 10^22 N
Explanation:
[tex]{ \bf{force = \frac{GM_{s} m _{e}}{ {r}^{2} } }}[/tex]
[tex]{ \sf{force = \frac{6.67 \times {10}^{ - 11} \times (2 \times {10}^{30} ) \times (6\times {10}^{24}) }{(1.5 \times {10}^{11}) {}^{2} } }} \\ \\ { \sf{force = 3.56 \times {10}^{22} \: newtons}}[/tex]
the hydrometer with the density of liquid to be 800 kg metre per square is the volume of the submerged part of the hydrometer is 5 into 10 to the power minus 5 calculate the mass of the hydrometer
Answer:
Mass = 0.04 Kg
Explanation:
Given the following data;
Density = 800 kg/m³
Volume = 5 * 10^{-5} m³
To find the mass of the object;
Density can be defined as mass all over the volume of an object.
Simply stated, density is mass per unit volume of an object.
Mathematically, density is given by the formula;
[tex] Density = \frac {mass}{volume} [/tex]
Making mass the subject of formula, we have;
[tex] Mass = density * volume [/tex]
Substituting the values into the formula, we have;
[tex] Mass = 800 * 5 * 10^{-5} [/tex]
Mass = 0.04 Kg
An observer measures a 100 Hz Doppler shift as an ambulance goes by. At rest, the frequency of the ambulance's siren is 2,000 Hz. What is the speed of the ambulance?
The change in the frequency of the sound, due to the relative motion of the source of sound and the observer, is determined by the Doppler's Effect.
The speed of the ambulance (source) is "6517 m/s"
The equation of Doppler's Effect is given as follows:
[tex]f_o = \frac{v+v_o}{v+v_s}f_s[/tex]
where,
[tex]f_o\\[/tex] = frequency of sound measure by observer = 100 Hz
v = speed of sound = 343 m/s
[tex]v_o[/tex] = speed of observer = 0 m/s
[tex]v_s[/tex] = speed of ambulance (source) = ?
[tex]f_s[/tex] = actual frequency = 2000 Hz
Therefore, using the values, we get:
[tex]100\ Hz = \frac{343\ m/s + 0\ m/s}{343\ m/s + v_s}(2000\ Hz)\\\\(100\ Hz)(343\ m/s + v_s) = (343\ m/s)(2000\ Hz)\\\\v_s = \frac{686000\ Hz.m/s - 34300\ Hz.m/s}{100\ Hz}[/tex]
v_s = 6517 m/s
Learn more about Doppler's Effect here:
https://brainly.com/question/1330077?referrer=searchResults
What do you mean by unit?
Unit is the quantity of a constant magnitude which is used to measure the magnitudes of other quantities of the same nature.
Answer:
The standard known quantity which is used to measure a physical quantities is known as unit.
Un muelle se alarga 20 cm cuando ejercemos sobre él una fuerza de 24 N. Calcula:El valor de la constante elástica del muelle
Answer:
120 Nm-1
Explanation:
Según la ley de Hooke;
F = Ke
F = fuerza sobre el resorte
K = constante de fuerza
e = extensión
Por eso;
K = F / e
K = 24N / 20 × 10 ^ -2m
K = 120 Nm-1
Kgms-1-= Ns ...solution
Answer:
units of impact or impulse or momnetum are same
These are
Kg m s-1 or N s
a teacher and two students are mesuring the speed of sound. the teacher makes loud sound by hitting two cymbals together. each students starts a stopwatch then they see the teacher hit the cymbals, they each stop their stop watch when they hear the sound. describe how a sound wave moves through the air.
Answer:
Slowly and smoothly lol
Answer:
S.I. on Rs. 1600 = T.D. on Rs. 1680. Rs. 1600 is the P.W. of Rs. 1680, i.e., Rs. 80 is on Rs. 1600 at 15%. Time =100 x 80year=1year = 4 months.1600 x 153
Explanation:
Is this you are?
PLEASE HELP!!
A set of water waves travels at 20.0 m/s , and 5.0 waves pass you in 4.0 s. What is the wavelengths of the waves?
a. 0.25 m
b. 8.0 m
c. 0.20 m
d. 4.0 m
Answer:
Explanation:
[tex]\lambda\\[/tex] = v/f
^That is the formula we are going to use.
Now, we were given the speed (v), which is 20.
Now we need to find frequency, in order to solve for the wavelength.
Frequency is the amount of waves in a fixed unit of one second, meaning our F value is the value of 5 divided by 4.
5/4 = 1.25
Therefore our F is 1.25
Now lets plug it in
[tex]\lambda\\[/tex] = v/f
[tex]\lambda\\[/tex] = 20/1.25
[tex]\lambda\\[/tex] = 16
Conversion:
[tex]\lambda\\[/tex] = 8
State newton's universal law of gravitation
Every particle of mass is attracted to every other particle of mass. The magnitude of the force between two objects is proportional to the product of their masses, and inversely proportional to the square of the distance between them. The direction of the force is along the line between their centers.
(NOTE: Newton's 3rd law of motion tells us that gravitational forces always come in pairs. Between two objects, there are two forces ... one in each direction. Their strengths are equal ... Your weight on Earth is exactly equal to the Earth's weight on YOU.)
A student project is required to be portable and hand held. It requires 6 V DC power at a current of 150 mA. The batteries for the power supply must last for a minimum of 7 hours of continuous operation. NiMH rechargeable batteries in AA size are to be used. A) How many batteries are needed
Answer:
a. 5 batteries b. 1050 mAh
Explanation:
Here is the complete question
A student project is required to be portable and hand held. It requires 6 V DC power at a current of 150 mA. The batteries for the power supply must last for a minimum of 7 hours of continuous operation. NiMH rechargeable batteries in AA size are to be used. A) How many batteries are needed? B) What mAh capacity should the batteries have?
Solution
A) How many batteries are needed?
Since the nominal voltage for a single NiMH battery is 1.2 V per battery and we require 6V DC power, we combine the batteries in series to obtain a total voltage of 6 V. The number of batteries required, n = total voltage/voltage per cell = 6V/1.2V per battery = 5 batteries
So, the number of batteries needed is 5.
B) What mAh capacity should the batteries have?
Since the batteries are in series, they would each deliver a current of 150 mA. Since we require a current of 150 mA for 7 hours, the number of milliampere-hours capacity mAh of batteries required is Q = It where I = current = 150 mA and t = time = 7 hours.
So, Q = It = 150 mA × 7 h = 1050 mAh.
So, the batteries should have a mAh of 1050 mAh
How do longshore currents shape the land?
Answer:
Longshore drift has a very powerful influence on the shape and composition of the coastline. It changes the slopes of beaches and creates long, narrow shoals of land called spits, that extend out from shore. Longshore drift may also create or destroy entire “barrier islands” along a shoreline.
Using deductive reasoning, write the converse, inverse, and contra positive of an if-then statement. Part I: Write an if-then statement below. (1 point)
Converse:
if q , then p
Inverse:
If not p , the not q.
Contra Positive:
If not q, then not p.
If then statement is a conditional statement. In this statement there is some condition at the first part of the sentence and then in the second part there is a conclusion.
The example of if then sentence is as follows,
If this camel is thirsty, then it will drink water from the well.
In this example there is a condition in first part that if camel is thirsty, in the second part there is conclusion which states that then it will drink water from well.
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A bullet with a mass mb=13.5 g is fired into a block of wood at velocity vb=245 m/s. The block is attached to a spring that has a spring constant k of 205 N/m. The block and bullet continue to move, compressing the spring by 35.0 cm before the whole system momentarily comes to a stop. Assuming that the surface on which the block is resting is frictionless, determine the mass mw of the wooden block.
Momentum is conserved, so the sum of the momenta of the bullet and block before collision is equal to the momentum of the combined bullet-block system,
[tex]m_bv_b+m_wv_w = (m_b+m_w)v[/tex]
where v is the speed of the bullet-block system. The block starts at rest so it has no initial momentum, and solving for v gives
[tex]v = \dfrac{m_b}{m_b+m_w} v_b[/tex]
The total work W performed by the spring on the bullet-block system as it is compressed a distance x is
[tex]W = -\dfrac12kx^2[/tex]
where k is the spring constant, and the work done is negative because the restoring force of the spring opposes the bullet-block as it compresses the spring.
By the work-energy theorem, the total work done is equal to the change in the bullet-block's kinetic energy ∆K, so we have
[tex]W_{\rm total} = W = \Delta K[/tex]
The bullet-block starts moving with velocity v found earlier and comes to a stop as the spring slows it down, so we have
[tex]-\dfrac12kx^2 = -\dfrac12(m_b+m_w)v^2 \implies kx^2 = \dfrac{{m_b}^2}{m_b+m_w}{v_b}^2[/tex]
Solve for [tex]m_w[/tex]:
[tex]m_w=\dfrac1k\left(\dfrac{m_bv_b}x\right)^2-m_b[/tex]
[tex]m_w=\dfrac1{205\frac{\rm N}{\rm m}}\left(\dfrac{(0.0135\,\mathrm{kg})\left(245\frac{\rm m}{\rm s}\right)}{0.350\,\rm m}\right)^2-0.0135\,\mathrm{kg}\approx \boxed{0.422\,\mathrm{kg}}[/tex]
What is the purpose of the lab the importance of the topic and the question you are trying to answer?
perpose of lab is to store apparatus and do some experiment
Helps someone to know the exert lengh of something
