Answer:
True
Explanation:
The tensile stress, σ, on a solid cylindrical wire is given by the following relationship;
[tex]\sigma = \dfrac{F_t}{A_o}[/tex]
Where;
[tex]F_t[/tex] = The tensile force
[tex]A_o[/tex] = The original cross sectional area of the cylindrical wire = π·R²
R = The radius of the wire
Therefore;
[tex]F_t[/tex] = σ × [tex]A_o[/tex] = σ × π × R²
Therefore, the tensile force is directly proportional to the square of the radius of the cylindrical wire, and as the radius of the wire increases, which is by increasing the thickness of the wire, the tensile force is largely increased
The correct option is; True.
valancy of an atom is +2. what does it mean.
Answer: I hope you find it useful
Explanation: Group 2 elements have two valence electrons. The two valence electrons are easily lost in the formation of chemical bonds. Once the two electrons are lost, the atom then has a full outer shell and is therefore more stable.
so, if an atom has valency 2 , then it means that the atom can combine with 2 other atoms .
Robin fired a bullet of mass 100 gm from a gun of mass 5 kg. The bullet leaves the gun with a speed of 400 m/s. After penetrating 4 cm of a plank of 10 cm, the bullet loses one third of its initial velocity.
a. Calculate the backward velocity of the gun?
b. Can the bullet penetrate the plank of the wood completely? Explain mathematically.
please help
(a) The recoil or backward velocity of the gun is 8 m/s.
(b) The bullet cannot penetrate the plank of the wood completely.
The given parameters include;
mass of the bullet, m₁ = 100 g = 0.1 kgmass of the gun, m₂ = 5 kginitial velocity of the bullet, u₁ = 400 m/sthickness of the plank, x = 10 cm(a) The backward or recoil velocity of the gun is calculated by applying the principle of conservation of linear momentum.
let the backward or recoil velocity of the gun = u₂m₁u₁ + m₂u₂ = 0
m₂u₂ = -m₁u₁
[tex]u_2 = -\frac{m_1u_1}{m_2} \\\\u_2 = - \frac{0.1 \times 400}{5} \\\\u_2 = -8 \ m/s[/tex]
Thus, the recoil or backward velocity of the gun is 8 m/s.
(b) determine if the bullet can penetrate the plank of the wood completely
the bullet traveled 4 cm and lost ¹/₃ of u₁the remaining distance to completely penetrate the plank = 6 cmthe final velocity of the bullet at 4 cm, v = 400 - ¹/₃ x 400 m/s = 266.67 m/sthe acceleration of the bullet is calculated as;
v² = u₁² + 2as
2as = v² - u²
[tex]a = \frac{v^2 -u_1^2}{2s} \\\\a = \frac{(266.67)^2 -(400)^2}{2\times 0.04} = -1.111 \times 10^6 \ m/s^2[/tex]
Finally, determine the distance traveled by the bullet when it comes to a complete stop, that is the final velocity = 0
[tex]v_f^2 = v^2 + 2ad\\\\2ad = v_f^2 - v^2\\\\d = \frac{v_f^2 - v^2}{2a} \\\\d = \frac{(0) - (266.67)^2}{2(-1.111\times 10^6)} \\\\d = 0.032 \ m[/tex]
d = 3.2 cm
The total distance traveled by the bullet inside the plank = 4 cm + 3.2 cm = 7.2 cm
Therefore, the bullet cannot penetrate the plank completely.
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Part B After producing electricity in many different ways, describe what causes electricity to flow in the coil? In your response, describe the types of forces acting on the electrons and how they result in movement.
Explanation:
If a coil of wire is placed in a changing magnetic field, a current will be induced in the wire. ... A changing magnetic field through a coil of wire therefore must induce an emf in the coil which in turn causes current to flow.
Due to the flow of the current run, the coil magnetic field is produced. Magnetic fields result in magnetic force.
What is electric force?The electric force between the two charges is directly propotional to the product of the charge and inversly propotional to the square of the distance between them.
A current will be generated in a wire coil if it is put in a changing magnetic field. As a result, a changing magnetic field through a coil of wire must create an emf in the coil, causing the current to flow.
A current is induced in a coil of wire when it is put in a changing magnetic field. Something generates an electric field that drives the charges around the wire, causing the current to flow.
Hence due to the flow of the current in the coil magnetic field is produced.
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Describe the laws of liquid pressure and Explain the term fluid. (Please give the correct answer, it's really urgent)
Answer:
The laws of liquid pressure are
(i) Pressure inside the liquid increases with the depth from the free surface of the liquid.
(ii) Pressure is same at all points on a horizontal plane, in case of stationary liquid.
(iii) Pressure is same in all directions about a point inside the liquid.
(iv) Pressure at same depth is different in different liquids. It increases with the increase in the density of the liquid.
(v) A liquid will always seek its own level.
A Fluid is any liquid or gas or generally any material that cannot sustain a tangential, or shearing, force when at rest.
Explanation:
why do the other animals listen to old major speak in the barn late on night?
You toss an apple across the room to a friend. Which of the following statements is true about the apple at the top of its trajectory?
A. Its acceleration is zero.
B. The horizontal component of its velocity is zero.
C. The vertical component of its velocity is 9.8 m/s down.
D. Its acceleration is 9.8 m/s2 down.
please help me with my question I will like and mark as brainliest for the first correct answer due tomorrow morning
Answer:
1845.26 ?
Explanation:
18.46 × 99.96= 1845.2616 = 1845.26
im not entirely sure though
Joseph jogs from one end A to the other end B of a straight 300 m road in 2 minutes 30 seconds and then turns around and jogs 100 m back to point C in another 1 minute. What are Joseph's average speeds and velocities in jogging (a) from A to B and (b) from A to C?
Answer:
Explanation:
(a) It is given that Joseph jogs on a straight road of 300m in a time interval of 2 minutes and 30 seconds, which is equal to 150seconds. Therefore, when Joseph jogs from point A to point B, he covers a distance of 300m in time of 150seconds. Hence, his average speed is 300m/150s=2ms^−1. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m. Since it is a straight road and he jogs in a single direction in this case, his displacement is equal to 300m.
Hence, his average velocity is 300m/150s=2ms^−1
(b) Then it is given that he turns back and points B and jogs on the same road but in the opposite direction for a time interval for 1 minute and covers a distance of 100m.If we consider the whole motion of Joseph, i.e. from point A to point C, then he covers a total distance of 300m+100m=400m. And he covers this total distance in a time interval of 2.5min+1min=3.5min=210s.
Therefore, his average speed for this journey is 400m210s=1.9ms−1.
For the same journey is displacement is equal to the distance between the points A and C,i.e. 300m−100m=200m.
Hence, his average velocity for this case is 200m/210s=0.95ms^−1
An imaginary star is four light years from earth. The star has a planet, upon which a large mirror has been installed. The mirror faces earth. A ten year old boy aims his telescope at the mirror. How old will the boy be when he sees his own reflection?
Answer:
14 years
Explanation:
because the light will take four years to reach the earth. And the star is four light years away from the earth.
Hope that helps you please followAn imaginary star is four light years from earth. The star has a planet, upon which a large mirror has been installed. The mirror faces earth. A ten year old boy aims his telescope at the mirror,then the boy would be 14 years old when he will see his own reflection.
What is a light year?
It can be defined as the distance travelled by the light in one year .it is represented in units of distance such as miles or km.
1 light year is calculated by multiplying the speed of light with the time of one year
1 light year = speed of light × one year time period
1 light year = 3×10⁸ ×(365×24×60×60)
=9.461× 10¹⁵ meter
As given in the problem 10 year old boy aims his telescope at the mirror which is 4 light years away then the light has to travel four years to reach the boy ,then the boy would be 14 year old when he would see his own reflection.
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a busis moving with the initial velocity 10m/s . after 4 seconds, the velocity becomes 30m/s . find the acceleration produce by bus,......please I need help
Answer:
5 m/s²
Explanation:
Use the acceleration formula: [tex]a=\frac{v_f-v_i}{t}[/tex]
a = acceleration (m/s²)vf = final velocity (m/s)vi = initial velocity (m/s)t = time (s)Based on the information given to us by the prompt, we know:
vi = 10 m/svf = 30 m/st = 4 sSubstitute these values for the variables to calculate the acceleration:
[tex]a=\frac{30-10}{4}\\\\a=\frac{20}{4}\\\\a=5[/tex]
Therefore, the acceleration of the bus is 5 m/s².
mercury is commonly used in thermometer give reasons
Answer:
hi
BECAUSE MERCURY IS USED BECAUSE IT is the only liquid available in room temperatureExplanation:
pls mark as a BRAINLIST
9. Which of the following is NOT a recommendation to help you succeed in this course?
Consistently and actively work in the course on a daily basis.
Wait until the end of the semester to complete all work.
Complete all assignments in a timely manner.
Contact your instructor if you have questions.
Answer:
Wait until the end of the semester to complete all work.
Explanation:
this is the obvious answer.
please mark me brainliest
Answer:
Wait until the end of the semester to complete all work
Two stones are dropped from the edge of a 60m cliff , the second stone 1.6secon after the first . How far below the top of the cliff is the second stone when the separation between the two stone is 36m?
Answer:
The separation between the two stones is 36 m, when the second stone is approximately 10.9 m below the top of the cliff
Explanation:
The given parameters are;
The height of the cliff from which the stones are dropped, h = 60 m
The time at which the second stone is dropped = 1.6 seconds after the first
The distance below the top of the cliff when the distance between the two stones is 36 m = Required
We have;
The kinematic equation of motion that can be used is s = u·t - (1/2)·g·t²
For the first stone, we have, s₁ = u·t₁ - (1/2)·g·t₁²
For the second stone, we get; s₂ = u·t₂ - (1/2)·g·t₂²
t₁ = t₂ + 1.6
g = The acceleration due to gravity ≈ 9.81 m/s²
s = The distance below the cliff top
The initial velocity of the stones, u = 0
Let t represent the time from which the second stone is dropped at which the distance between the two stones is 36 m, we have;
s₁ = u·(t + 1.6) + (1/2)·g·(t + 1.6)²
s₂ = u·t + (1/2)·g·t²
u = 0
∴ s₁ - s₂ = 36 = (1/2)·g·(t + 1.6)² - (1/2)·g·t²
2 × 36/(g) = (t + 1.6)² - t² = t² + 3.2·t + 2.56 - t² = 3.2·t + 2.56
2 × 36/(9.81) = 3.2·t + 2.56
t = (2 × 36/(9.81) - 2.56)/3.2 = ≈ 1.49 s
t ≈ 1.49 s
s₂ = (1/2)·g·t²
∴ s₂ = (1/2) × 9.81 × 1.49² ≈ 10.9
The distance below the top of the cliff of the second stone when the the separation between the two stones is 36 m, s₂ ≈ 10.9 m.
A pulley system is made of 3 pulley write its velocity ratio
Almost 3 times fast than normal pulley system
mark me
Give reason.
b} String roller is an example of wheel and axel .Why?
Explanation:
string roller is called an example of wheel and axel because The thin rod which needs to be turned is called the axle and the wider object fixed to the axle, on which we apply force is called the wheel.
hence the we apply force on the roller and the string gets tight.
Ley de Charles-.
1) En un recipiente hermético se tiene 150 ml de una sustancia gaseosa, a una temperatura de 115°C, esto como resultado de una reacción. ¿Cuál sería su volumen inicial, cuando su temperatura era de 100°C?
2) Al inicio cuando la temperatura es de 200°C, se tienen 350 ml de un gas “Y”. ¿Qué volumen se obtendrá si la temperatura se incrementa a 250°C?
Tomando en cuenta la Ley de Charles y la condiciones dentro del recipiente, tenemos las siguientes conclusiones con respecto al volumen del recipiente:
1) El volumen inicial del gas es 144.203 mililitros.
2) El volumen final del gas es 386.986 mililitros.
La Ley de Charles establece que el Volumen de un gas es directamente proporcional a su Temperatura, basados en este hecho, podemos resolver los problemas en cuestión mediante la siguiente relación matematica:
[tex]\frac{V_{1}}{T_{1}} = \frac{V_{2}}{T_{2}}[/tex] (1)
Donde:
[tex]V_{1}[/tex] - Volumen inicial, en mililitros.
[tex]V_{2}[/tex] - Volumen final, en mililitros.
[tex]T_{1}[/tex] - Temperatura inicial, en Kelvin.
[tex]T_{2}[/tex] - Temperatura final, en Kelvin.
1) Si sabemos que [tex]V_{2} = 150\,mL[/tex], [tex]T_{2} = 388.15\,K[/tex] and [tex]T_{1} = 373.15\,K[/tex], entonces el volumen inicial del gas es:
[tex]V_{1} = \frac{T_{1}}{T_{2}}\times V_{2}[/tex]
[tex]V_{1} = \frac{373.15\,K}{388.15\,K}\times 150\,mL[/tex]
[tex]V_{1} = 144.203\,mL[/tex]
El volumen inicial del gas es 144.203 mililitros.
2) Si sabemos que [tex]T_{1} = 473.15\,K[/tex], [tex]V_{1} = 350\,mL[/tex] and [tex]T_{2} = 523.15\,K[/tex], entonces el volumen final del gas es:
[tex]V_{2} = \frac{T_{2}}{T_{1}}\times V_{1}[/tex]
[tex]V_{2} = \frac{523.15\,K}{473.15\,K}\cdot 350\,mL[/tex]
[tex]V_{2} = 386.986\,mL[/tex]
El volumen final del gas es 386.986 mililitros.
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Give reason Pascal is a derived unit
Answer:
Pascal is a derived unit because it cannot be expressed in any physics terms, but it is an expression of fundamental quantities.
Explanation:
[tex]{ \sf{Pasacal \: ( Pa) = \frac{newtons}{metres {}^{2} } }} \\ \\ { \sf{Pasacal \: (Pa) = \frac{kg \times {ms}^{ - 2} }{ {m}^{2} } }}[/tex]
A rod is made up of copper and wood joined together.
After the rod is heated at the join in the centre for about a minute, where would the lowest temperature be?
my views
Explanation:
Figure (8) shows a rod made up of copper and wood joined together. The rod is heated at the joint in the centre for about a minute. At which point – A, B, C or D, would it show the lowest temperature? PLEASE GIVE REASONS ALSO(MINIMUM 2)
List two factors that compression force depends on
The magnitude (size or numerical value) and the direction.
Hope this helps!!! :)
how do atoms lose electrons ?
Answer:
Explanation:
By being close to an atom that will gladly take the electrons being offered.
Suppose you are talking about Be. It is in the second column. It has two outer electrons that can be given away. It will not give away one of the two remaining electrons because they are too close to the + nucleus.
Along comes a Fluorine atom. It has 7 electrons in its outer ring. The chemistry of the situation allows it to take on one of the two electrons Be is offering. It is all a matter of charges and attractions.
Another Fluorine atom will take on the remaining electron from the Be. The outer ring cannot take on more than 1 electron, but that is enough
If we increase the surface area of a given surface without changing the force acting on it, then the pressure acting on it will ______ (increase/decrease/remain the same)
Answer:
Decrease
Explanation:
The pressure is the force per unit area. So, P=F/A
Thus the pressure P is inversely proportional to contact area A.
So when area increases , the pressure will be decreasing.
Which of the following is an exa example of a wave
Longitudinal waves
Transverse waves
Electromagnetic Waves
Water waves
Rope waves
LIght Waves
find the expression for the displacement covered in nth or in last one second
Answer:
Snth = u + a/2 ( 2n - 1)
Explanation:
Do you need explanation based on graph, integration or other method?
any person who opens the door he applies
Answer:
any person who opens the door he applies pulling force
A car horn creates a 595 Hz tone at rest. Two cars pass on the street, each going 20.0 m/s; the first car honks. What frequency does the other car hear before they pass each other?
Doppler frequency, the other car hear before they pass each other is 668.68 Hz.
What is frequency?Frequency is the number of occurrences of a repeating event per unit of time.
What is Doppler EFFECT?The Doppler effect is the change in frequency of a wave in relation to an observer who is moving relative to the wave source.
According to the Doppler Effect, the frequency observed is
[tex]fo=fs\frac{v+v_{o} }{v-v_{s} }[/tex]
[tex]f_{o}=595\frac{343+20 }{343-20 }\\f_{o} = 668.68 Hz[/tex]
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An observer is standing next to the tracks, watching a train approach. The train travels at 30 m/s and blows its whistle at 8,000 Hz as it approaches and then passes by the observer without slowing down. Assuming the speed of sound is 340 m/s, how much of a frequency change did the observer hear?
7351.35Hz
f0= v-Vo/v-Vs × FSA
= 340-0 /340+30 ×8000
= 340/370× 8000
= 7351.35hz
The hydro power plant transforms one form of energy into another. However, the total amount
of energy of the water stays the same until it enters the turbine.
Explain how this statement is supported by the three column charts above.
*attached is the column charts
The hydro power plant consists of a (artificial) dam that builds gravitational potential energy, P.E. from natural flowing water sources, by locating the dam along the water path. The stored potential energy, P. is converted into kinetic energy, K.E. as the water falls from the dam, down to the turbines, located at a much lower level according to the following principle of conservation of energy equation;
Total Mechanical Energy, M.E. = The potential energy of the water, P.E. + The kinetic energy of the water, K.E. = Constant
M.E. = P.E. + K.E. = Constant
Where;
P.E. = m·g·h
K.E. = (1/2)·m·v²
m = Mass
g = The acceleration due to gravity
h = The height of the dam
v = The velocity
The charts can be explained as follows;
Given that the potential energy P.E. = m·g·h, we have that the potential energy is directly proportional to the height of the dam, and therefore, at mid height, the potential energy would be half the maximum value, and we have;
At mid height, P.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex]
At the top of the dam, the (vertical) velocity of the water = 0, therefore, the kinetic energy = 0
Therefore, at the top of the dam, we get;
M.E. = [tex]P.E._{max}[/tex] + 0 =
M.E. = [tex]\mathbf{P.E._{max}}[/tex]
Similarly, at the bottom of the dam, the height, h = 0, therefore, being proportional to the height, P.E. = 0, and the velocity is maximum, and at the bottom, we have;
M.E. = 0 + [tex]K.E._{max}[/tex]
The first chart, water is halfway down the dam
At the halfway down therefore, we have;
P.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex]
M.E. = [tex]P.E._{max}[/tex] = (1/2)·
∴ K.E. = [tex]P.E._{max}[/tex] - (1/2)·
Therefore the first chart, water is halfway down the dam;
Halfway, K.E. = (1/2)·[tex]\mathbf{P.E._{max}}[/tex] = P.E.
∴ K.E. = P.E. as shown on the chart
The second chart, water has reached the turbine
Water reaches the turbine at the bottom, and as explained above, we get;
M.E. = 0 + [tex]K.E._{max}[/tex]
∴ M.E.≈ [tex]K.E._{max}[/tex]
Therefore, when water has reached the turbine at the bottom of the dam, the kinetic energy is approximately proportional to the total mechanical energy as shown in the chart
The third chart, water is at the top of the dam
Here as shown above, we have;
The total mechanical energy, M.E. ≈ [tex]\mathbf{P.E._{max}}[/tex] as shown on the chart
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A force of 150N at an angle of 60 degree to the horizontal to pull a box through a distance of 50m calculate the work done
[tex]\boxed{\sf W=Fscos\Theta}[/tex]
[tex]\\ \sf\longmapsto W=150(50)cos 60[/tex]
[tex]\\ \sf\longmapsto W=7500\times \dfrac{1}{2}[/tex]
[tex]\\ \sf\longmapsto W=3750J[/tex]
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 ?
Answer:
Explanation:
We first need to convert the 40 km/h to m/s. Going by the fact that 40 has only 1 significant figure in it, 40 km/h = 10 m/s. The rest of the values are in their proper labels. We will use the equation:
[tex]v^2=v_0^2+2a[/tex]Δx where the final velocity is 0 because the car is coming to a stop at the end; the initial velocity is 10 m/s, the acceleration (or, rather, deceleration) is -.5 m/s/s, and our unknown which is displacement. Filling in:
[tex]0=(10)^2+2(-.5)[/tex]Δx and solving for Δx:
Δx = [tex]\frac{-100}{2(-.5)}[/tex] which ends up being simply that
Δx = 100 m
Two representative elements are in the same period of the periodic table. Which statement correctly describes the atoms of the two elements?(1 point)
They have the same number of electrons.
They have the same number of valence electrons.
They have valence electrons in different energy levels.
They have valence electrons in the same energy level.
Answer:
Elements in the same group have the same number of valence electrons.
When moving right across a period, the valence electrons of the main group elements increase by one.
When moving down a group, the valence electrons of the main group elements increase by one.
Elements in the same period have the same number of valence electrons.
Elements in the same period of the periodic table have valence electrons in the same energy levels.
When elements are in the same period on the periodic table, it means that they have the same number of shells.
The energy level of valence electrons in a atom depends on how far it is from the nucleus. This means that:
Valence electrons on elements in the same period will be the same distance from their nucleus They will have the same energy level as they are equally attracted to their nucleusFor instance, Boron, Carbon and Nitrogen will have valence electrons in the same energy levels.
In conclusion, elements in the same period will have valence electrons in the same energy levels.
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