Answer:
Efficiency of a machine is 90% this means that the total energy produced to the machine only 90% is useful and given as a output.
Machines are not 100% efficient because some of the work done by a machine is used to overcome friction
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:
Can someone help me please this test is very important
Answer:
Friction is caused in roller coasters by the rubbing of the car wheels on the track and by the rubbing of air (and sometimes water!) against the cars.
Explanation:
A rocket blasts off. In 10.0 seconds it is at 10,000 ft, traveling at 3600 mph. Assuming the direction is up, calculate the acceleration.
Answer:
Explanation:
Givens
t = 10 seconds
vi = 0
vf = 3600 mph
a = ?
d = 10000 feet
Formula
a = (vf - vi)/t
Solution
vf = 3600 mph * 1 hr / 3600 seconds * 5280 feet / 1 mile = 5280 ft / sec
a = (5280 - 0)/10
a = 528 ft/sec^2
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?
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
Which class of lever has all advantages of lever
Answer:
Helo ....
so this answer would be First class levers
becoz...
First-class levers have a considerable practical advantage over the other types of levers. They convert a downward moving force into a lifting force
is it possible to mark it brainliest <3
The 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:
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.
Learn more at https://brainly.com/question/24294393
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
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 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?
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
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
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 load of 800 newton is lifted by an effort of 200 Newton. if the load is placed at a distance of 10 cm from the fulcrum. what will be the effort distance ?
Answer:
40 cm
Explanation:
We are given that
Load=800 N
Effort=200 N
Load distance=10 cm
We have to find the effort distance.
We know that
[tex]load\times load\;distance=Effort\times effort\;distance[/tex]
Using the formula
[tex]800\times 10=200\times effort\;distance[/tex]
Effort distance=[tex]\frac{800\times 10}{200}[/tex]
Effort distance=[tex]\frac{8000}{200}[/tex]
Effort distance=40 cm
Hence, the effort distance will be 40 cm.
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
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.
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/mIt takes Serina 1.81 hours to drive to school. Her route is 36 km long. What is Serina's average speed on her drive to school?
Answer:
60
Explanation:
because it shows he is moving at a low speed
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.
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
Define the term ‘matter’ in physics.
Answer:
Matter is any substance that has mass and takes up space by having volume
A 63 kg kg person starts traveling from rest down a waterslide 6.0 mm above the ground. At the bottom of the waterslide, it then curves upwards by 1.0 mm above the ground such that the person is consequently launched into the air. Ignoring friction, how fast is the person moving upon leaving the waterslide
Answer:
change waterslide according to question. and you are good to go. check photo for solve
The person moving with speed upon leaving the waterslide is equal to 0.313 m/s while ignoring the friction.
What is the law of conservation of energy?If there is a loss of energy in any part of the system, there must be the same amount of a gain of energy in some other part of the isolated system.
Kinetic energy + Potential energy = constant
Therefore, the initial kinetic and potential energy of the person must be equal to the final kinetic and potential energy.
mgh₁ + mv₁²/2 = mgh₂ + mv₂²/2
gh₁ + v₁²/2 = gh₂ + v₂²/2
2gh₁ + v₁² = 2gh₂ + v₂²
2g(h₁ - h₂) = v₂² - v₁²
[tex]v_2=\sqrt{2g(h_2-h_1) + v^2_1}[/tex] .................(1)
Given, the mass of the person, m = 63 Kg
The initial speed of the person as at rest, v₁ = 0
Consider that the speed of the person while leaving the waterslide is v₂
The initial height of the person above the ground, h₁ = 6.0 mm
The height of the person leaving the waterslide, h₂= 1.0 mm
Substitute, the value of m, v₁, h₁ and h₂ in equation (1):
[tex]v_2 = \sqrt{2(9.8m/s^2)(6mm-1mm) + (0)^2}[/tex]
[tex]v_2 =\sqrt{2(9.8)\times 5 \times 10^{-3}} \;m/s[/tex]
[tex]v_2 =\sqrt{0.098}\; m/s[/tex]
v₂ = 0.313 m/s
Learn more about the law of conservation of energy, here:
https://brainly.com/question/12050604
#SPJ2
define mass defect and binding energy
Answer:
About Transcript. Nuclear binding energy is the energy required to split an atom's nucleus into protons and neutrons. Mass defect is the difference between the predicted mass and the actual mass of an atom's nucleus. The binding energy of a system can appear as extra mass, which accounts for this difference.
Explanation:
PLZ MARK AS THE BRAINLIEST
I NEED IT URGENTLY
HAVE A GOOD DAY
MAY GOD BLESS U
: )
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
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 !!!!!!!
7. A thin wire was wound 30 times closely over a boiling tube. The total length of the windings as measured was found to be 6.3mm. Determine the diameter of the wire .
Answer:
Diameter of wire = 0.00021 meters
Explanation:
Given the following data;
Number of windings = 30
Length of windings = 6.3 mm to meters = 0.0063 meters
To find the diameter of the wire, we would use this mathematical expression;
Length of windings = number of windings * diameter of wire
Substituting the values into the expression, we have;
0.0063 = 30 * diameter of wire
Diameter of wire = 0.0063/30
Diameter of wire = 0.00021 meters
An astronaut on Pluto attaches a small brass ball to a 1.00-m length of string and makes a simple pendulum. She times 10 complete swings in a time of 257 seconds. From this measurement she calculates the acceleration due to gravity on Pluto. What is her result
Answer:
The acceleration due to gravity at Pluto is 0.0597 m/s^2.
Explanation:
Length, L = 1 m
10 oscillations in 257 seconds
Time period, T = 257/10 = 25.7 s
Let the acceleration due to gravity is g.
Use the formula of time period of simple pendulum
[tex]T = 2\pi\sqrt{\frac{L}{g}}\\\\25.7 = 2 \times 31.4\sqrt{\frac{1}{g}}\\\\g = 0.0597 m/s^2[/tex]
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
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.
