Answer:
f = 15 N
Explanation:
It is given that, when you push with a horizontal 15-N force on a book that slides at constant velocity, a frictional force also acts on it. Frictional force is an opposing force. The magnitude of applied force and frictional forces are same. So, the force of friction on the book is equal to 15 N.
In any case, resistance of a material is a measure of the quantity of
present in the materials.
Answer:
free electrons
Explanation:
Answer:
free electrons
Explanation:
Gamma radiation can be significantly reduced by…
A sheet of paper
Air
A 3 mm thickness of aluminium
Several cm of lead
Answer:
Several cm of lead
Explanation:
The average kinetic energy of the molecules of an ideal gas at 10∘C has the value K10. At what temperature T1 (in degrees Celsius) will the average kinetic energy of the same gas be twice this value, 2K10? Express the temperature to the nearest integer. View Available Hint(s) T1 T 1 T_1 = nothing ∘C Part B The molecules in an ideal gas at 10∘C have a root-mean-square (rms) speed vrms. At what temperature T2 (in degrees Celsius) will the molecules have twice the rms speed, 2vrms? Express the temperature to the nearest integer. View Available Hint(s) T2 T 2 T_2 = nothing ∘C
Answer:
A) T1 = 566 k = 293°C
B) T2 = 1132 k = 859°C
Explanation:
A)
The average kinetic energy of the molecules of an ideal gas is givwn by the formula:
K.E = (3/2)KT
where,
K.E = Average Kinetic Energy
K = Boltzman Constant
T = Absolute Temperature
At 10°C:
K.E = K10
T = 10°C + 273 = 283 K
Therefore,
K10 = (3/2)(K)(283)
FOR TWICE VALUE OF K10:
T = T1
Therefore,
2 K10 = (3/2)(K)(T1)
using the value of K10:
2(3/2)(K)(283) = (3/2)(K)(T1)
T1 = 566 k = 293°C
B)
The average kinetic energy of the molecules of an ideal gas is given by the formula:
K.E = (3/2)KT
but K.E is also given by:
K.E = (1/2)(m)(vrms)²
Therefore,
(3/2)KT = (1/2)(m)(vrms)²
vrms = √(3KT/m)
where,
vrms = Root Mean Square Velocity of Molecule
K = Boltzman Constant
T = Absolute Temperature
m = mass
At
T = 10°C + 273 = 283 K
vrms = √[3K(283)/m]
FOR TWICE VALUE OF vrms:
T = T2
Therefore,
2 vrms = √(3KT2/m)
using the value of vrms:
2√[3K(283)/m] = √(3KT2/m)
2√283 = √T2
Squaring on both sides:
(4)(283) = T2
T2 = 1132 k = 859°C
A) The temperature at which the average kinetic energy will have a value of 2K10 is; T1 = 293 °C
B) The temperature at which the molecules have twice the rms speed, 2vrms is; T2 = 859 °C
A) We are given;
Initial temperature; T = 10°C = 283 K
Initial kinetic energy; KE = K10
Final kinetic energy; KE1 = 2K10
Now,formula for average kinetic energy of the molecules of an ideal gas is given as;
KE = (3/2)kT
Where;
k is Boltzmann constant
T is temperature
We are told that in the second case, KE = 2K10. Thus;
2K10 = (3/2)kT1
K10 = ¾kT1 - - - (eq 2)
In the first instance, we have;
K10 = (3/2)kT - - - (eq 1)
Put (3/2)kT for K10 in eq 2 to get;
(3/2)kT = ¾kT1
k will cancel out to get;
(3/2)T = ¾T1
Make T1 the subject to get;
T1 = 2T
Thus;
T1 = 2 × 283
T1 = 566 K
Converting to °C gives;
T1 = 293 °C
B) We want to find the temperature T2 (in degrees Celsius) at which the molecules will have twice the rms speed, 2v_rms.
Formula for kinetic energy is also;
KE = ½mv²
Thus;
½m(v_rms)² = (3/2)kT
v_rms = √(3kT/m) - - - (eq 1)
When rms speed is 2v_rms, we have;
½m(2v_rms)² = (3/2)kT2
v_rms = √(¾kT2/m) - - - (eq 2)
Thus;
√(3kT/m) = √(¾kT2/m)
Square both sides to get;
(3kT/m) = (¾kT2/m)
4T = T2
T2 = 283 × 4
T2 = 1132 K
Converting to °C gives;
T2 = 859 °C
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Which of the following choices is a characteristic of the Baroque period?
clear melodies
simplified orchestration
emotional meaning
grandeur
Answer: C
emotional meaning
Explanation:
Baroque style in the Baroque period is an ancient way of variety of arts used to produce European uniqueness in many art works such as magnificence in sculpture, painting, architecture, literature, dance, music and drama.
The characteristic of the Baroque period that helped to achieve all these is the extravagant display of emotions and details orientation.
A running man cannot stop as soon as he wants to stop. Explain why ?
Plz reply fast
Answer:
mass is not eager to be accelerated or in this case slowed down.
Explanation:
In general, Newton's 1st law states that every object will remain at rest or in uniform motion in a straight line unless compelled to change its state by the action of an external force.
What this means is that a mass is not eager to be accelerated or in this case slowed down. It will require an external force (muscle power) to get the mass of a running man to slow down. It is not instant also, because it takes time to slow down.
EXTRA
Supose the running man would try to stop instantly by purposely running against a brick wall. Even in that case, there is a small amount of time needed ( a fraction of a second perhaps) in which the moving mass of the man is forced to stop moving. That force is usually so huge, that it will injure someone in case of a crash, which might result even in death!
The purpose of an airbag or wearing a helmet, is to extend the time during a crash, FROM 0 to close to zero.
The layer of foam inside a helmet, protects the head in case of a crash, because it takes an amount of time for the head to squash the foam inside the helmet because the mass needs to be stopped ALMOST instantly. That difference between zero seconds and maybe 1 second, is sometimes enough to be able to survive a crash.
A projectile is launched with an initial velocity of 25 m/s at an angle of 30° above the horizontal. The projectile reaches maximum height at point p then falls to point a, which is 65 m below the cliff. What is the horizontal distance that it travels (labeled x in the diagram)
Answer:
x ≈ 56 m
Explanation:
vertical initial velocity =[tex]v_{0y}(t)[/tex] = 25 m/s* sin(30°)= 12.5 m/s
height = h
[tex]h =v_{0y}t+\frac{at^{2}}{2} \\\\65m = 12.5m/s*t + \frac{9.8m/s^{2}*t^{2}}{2} \\\\t=2.584 s[/tex]
t- time is found solving quadratic equation.
horizontal velocity = [tex]v_{0x}=25m/s*cos(30^{o})=21.65 m/s[/tex]
Horizontal velocity is constant, so distance [tex]x=v_{0x}*t =21.65 m/s *2.584 s=55.9 = 56 m[/tex]
The horizontal distance travelled by the object will be "111.07 m".
According to the question,
[tex]u_v = u sin\Theta[/tex]
[tex]= 25 \ sin30^{\circ}[/tex]
[tex]= 12.5 \ m/s[/tex]
As we know,
→ [tex]s = ut +\frac{1}{2} at^2[/tex]
[tex]-y = u_vt-\frac{1}{2}gt^2[/tex]
[tex]-65 =12.5t - \frac{1}{2}\times 9.8t^2[/tex]
[tex]0 = 4.9t^2-12.5t-65[/tex]
[tex]t = \frac{12.5 \pm \sqrt{(-12.5)^2-4\times 4.9\times (-65)} }{2\times 4.9}[/tex]
[tex]= 5.13 \ s[/tex]
hence,
The horizontal distance will be:
→ [tex]u_x = ucos \Theta[/tex]
[tex]= 25 cos 30^{\circ}[/tex]
[tex]= 21.65 \ m/s[/tex]
or,
→ [tex]x = 21.65\times 5.13[/tex]
[tex]= 111.07 \ m[/tex]
Thus the response above is right.
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In young's double silt experiment if the distance between the silts is 0.5 and the distance between the silts and screen is 2 times.Then what will be the width of bands
Answer: The width of bands will be 2λ
Explanation: Please see the attachments below
Two identical 82 mg dust particles very far apart (PEE 0) are moving directly toward each other at a speed of 3698 m/s. The charge on each is-719 ?C. Determine how close they will get to each other. Let k = 9x109 N-m2/C2 & ignore gravity.
Answer:
r = 4.139
Explanation:
In order to calculate how close the particles will get to each other, you take into account that all kinetic energy becomes electric potential energy between the particles when they are at the minimum distance. Then, you have:
[tex]U=K\\\\k\frac{q_1q_2}{r}=\frac{1}{2}m_1v_1^2+\frac{1}{2}m_2v_2^2[/tex] (1)
q1 = q2: charge of the dust particles = -719μC = -719*10^-6 C
m1 = m2: mass = 82mg = 82*10^-6 kg
v1 = v2: speed of both particles = 3698 m/s
k: Coulomb's constant = 8.98*10^9 Nm^2/C^2
You solve the equation (1) for r:
[tex]q_1=q_2=q\\\\m_1=m_2=m\\\\v_1=v_2=v\\\\k\frac{q^2}{r}=mv^2\\\\r=\frac{kq^2}{mv^2}[/tex]
Finally, you replace the values of all parameters:
[tex]r=\frac{(8.98*10^9Nm^2/C^2)(-719*10^{-6}C)^2}{(82*10^{-6}kg)(3698m/s)^2}\\\\r=4.139m[/tex]
hence, the distance at which both dust particle are closer to each other is r = 4.139m
An electric field is = (400 N/C) for x > 0 and = (–400 N/C) for x < 0. A cylinder of length 30 cm and radius 10 cm has its center at the origin and its axis along the x axis such that one end is at x = +15 cm and the other is at x = –15 cm. What is the net outward flux through the entire cylindrical surface?
Answer:
0 Nm²/C
Explanation:
We calculate the total flux Ф = ∫E.dA for -15 < x < 0 and 0 < x < 15
which is the flux through the curved sides + the flux through its ends.
So, Ф₁ = ∫₋₁₅⁰E.dA + ∫₀¹⁵E.dA this is the flux through the curved sides of the cylinder
Ф₁ = ∫₋₁₅⁰EdAcos0 + ∫₀¹⁵EdAcos0 (since the area is parallel to the electric field)
Ф₁ = ∫₋₁₅⁰EdA + ∫₀¹⁵EdA
Ф₁ = E∫₋₁₅⁰dA + E∫₀¹⁵dA
= E∫₋₁₅⁰2πrdx + E∫₀¹⁵2πrdx
= E2πr∫₋₁₅⁰dx + E2πr∫₀¹⁵dx
= E2πr[x]₋₁₅⁰ + E2πr[x]¹⁵₀
= E2πr[0 -(-15)] + E2πr[15 - 0]
= (-400 N/C)2πr[15] + (+400 N/C)2πr[15]
= -800 N/Cπ(0.30 m )[0.15 m] + 800 N/Cπ(0.30 m)[0.15]
= (-36επ + 36επ) Nm²/C = 0
the flux through the ends is
Ф₂ = ∫₋₁₅⁰E.dA + ∫₀¹⁵E.dA
= ∫₋₁₅⁰EdAcos0 + ∫₀¹⁵EdAcos0 (since the area is parallel to the electric field)
= ∫₋₁₅⁰EdA + ∫₀¹⁵EdA
= E∫₋₁₅⁰dA + E∫₀¹⁵dA
= (-400 N/C)πr² + (400 N/C)πr²
= 0
So, the total flux equals Ф = Ф₁ + Ф₂ = 0 + 0 = 0 Nm²/C
The temperature of the air in a valley begins to increase after the sun comes up and heats the valley floor. What will
happen to the velocity of sound in this valley?
-The velocity will increase
-The veocity will decrease
-The velocity will not change
-The velocity will drop to zero.
Explanation:
I think it will increase a little bit ... just image ... if the temperature is 0, the velocity will be 0 too. because the vibration of atom is so weak and the sound cant progation.
Answer:
The velocity will increase.
Explanation:
Wave velocity and the temperature of the medium are directly proportional so if the temperature increases, the velocity will increase.
Some parents build their children’s lives around sports and place a high premium on the successes their children achieve in sports. Such parents often enroll their kids in sports programs when they are in preschool and continue to encourage their involvement in sports through high school and beyond. Many of these parents justify their position by equating success on the playing field with success in the real world. They also cite the benefits of sports to support their decisions: improving physical fitness, building lasting friendships, and acquiring life skills, such as persistence and teamwork. In light of this phenomenon, discuss the benefits and drawbacks to parental involvement in their children’s sports lives. When do parents cross the line between healthy encouragement to prepare their children for success and pushing them to succeed at all costs?
Answer:
I think they cross the line when they force sports into their child's life, and take away their choice of what they want to do so they essentially waste their childhood preparing for something that may never happen or they just don't get the opportunity to explore their artistic abilities.
Explanation:
A car weighing 1600 kg is accelerated to 30m/s from start in 20s. Calculate the
acceleration of the car and the magnitude of the force applied.
Answer:
Acceleration = 1.5m/s²Force applied = 2,400NExplanation:
Force is defined as the product of mass of an object and its acceleration.
Force = mass * acceleration and acceleration = velocity/time
Force = mass*(velocity/time)
Given Mass of the car = 1600kg, velocity = 30m/s and time taken = 20secs
Substituting this values in the formula will give;
Force = 1600 * 30/20
Force = 1600 * 1.5
Force = 2,400N
Magnitude of the force applied = 2,400N
Since acceleration = velocity/time
Acceleration = 30/20
Acceleration = 1.5m/s²
Acceleration of the car is 1.5m/s²
What’s the maximum height of the second hill? Use your answer from part E and the formula PE=m•g•h to determine the answer. Assume that g = 9.8m/sec2.
Answer:
111.4 m
Explanation:
PE = m x g x h
349,300 = 320 x 9.8 x h
h = 349300 : 3136
h = 111,384 m
A force of 5N compresses a spring by 4cm. Find the force constant of the spring.
Answer:
k = 1,250 N/m
Explanation:
Use the formula F=kx, with F=5N and x=0.04m
Then the spring constant (k) is 5/0.04
Distance travelled can be found from the
A area under a velocity-time graph
B area under an acceleration-time graph
C gradient of a force-time graph
D gradient of a velocity-time graph
Answer:
A
Explanation:
This is because distance traveled (i.e. displacement) is the integral of the velocity function, and velocity is the first derivative of the displacement function. To put this in perspective, the area bounded by a curve can be found by taking the integral of the equation of the curve, taking values on the x-axis as limits.
If the total momentum of a system of an old woman pushing a shopping cart is 450 kg×m/s, both with a velocity of 3 m/s, and the woman has a mass of 50 kg, what is the mass of the cart?
Answer:
100kg
Explanation:
Momentum is defined as the product of mass times velocity:
[tex]p=mv[/tex]
The total momentum M must be equal to the sum of momentums of the system components, in this case the momentum of the lady plus the momentum of the cart:
[tex]M=m_{woman}v_{woman}+m_{cart}v_{cart}[/tex]
since both the woman and the shopping cart have the same velocity:
[tex]v_{woman}=v_{cart}=v[/tex]
the equation becomes:
[tex]M=m_{woman}v+m_{cart}v\\M=v(m_{woman}+m_{cart})[/tex]
and since we need the mass of the cart we solve for [tex]m{cart}[/tex]:
[tex]m_{woman}+m_{cart}=\frac{M}{v} \\\\m_{cart}=\frac{M}{v} -m_{woman}[/tex]
the values given by the problem are the following:
total momentum: [tex]M=450kgm/s[/tex]
mass of the woman: [tex]m_{woman}=50kg[/tex]
velocity: [tex]v=3m/s[/tex]
we substitute all of them in the equation to find the mass of the shopping cart:
[tex]m_{cart}=\frac{450kgm/s}{3m/s} -50kg\\\\m_{cart}=150kg-50kg\\\\m_{cart}=100kg[/tex]
the mass of the cart is 100kg.
Which properties are characteristics of non metals
Non - Metals:
Non- metals are bad conductor of electricity ( except Graphite ).Non- metals are also bad conductor of heats. ( except diamond )Non - metal are neither malleable nor ductile. They are brittle. Non-metal are not strong. Non-metal are not sonorous.Some terms:
★ Malleable: This means that metals can be beaten into thin sheets with hammer.
★ Ductile: This means that metals can be drawn into thin wires.
★ Brittle: This means that non-metal break into pieces on hammering.
★ Sonorous: This means capable of producing a ringing sound.
Find the average speed of a car that is travelling 45 km in 5 hours. *
4 points
6 km/h
8 km/h
9 km/h
20 km/h
Answer:
9 km/h
Explanation:
Speed can be found using the following formula.
s=d/t
where d is distance and t is time.
The car traveled 45 kilometers in 5 hours.
d=45 km
t=5 h
Substitute these values into the formula
s=45 km/5 h
Divide 45 by 5
s=9 km/h
The average speed of the car is 9 kilometers per hour.
Your bone structure, metabolism and body fat distribution all contribute to your ______ A.Body type B. Height C. Energy levels D. Exercise habits
Answer:
Maybe [A]
Explanation:
What is the mass of a dog if it accelerates at 15 m/s^2 and has a force of 50 N?
Answer:
3.33kg
Explanation:
Force=mass×acceleration
Force=50N
Acceleration=15m/s^2
50=m×15
50=15m
50/15=15m/15
3.33=m
Therefore the mass is 3.33kg
When the crest of one wave passes through the trough of another wave, ____ takes place. A. resonance B. diffraction C. constructive interference D. destructive interference
When the crest of one wave passes through the trough of another wave, destructive interference takes place.
What is the crest of a wavelength?The crest and trough of a wave, respectively, are its highest and lowest surface portions. The wave height is the vertical distance between the peak and trough. The wavelength is the horizontal separation between two consecutive crests or troughs.
When the crest of one wave passes through the trough of another wave, interference takes place.
This interference can be constructive, where the amplitudes of the waves add up, resulting in a larger wave, or destructive, where the amplitudes of the waves cancel out, resulting in a smaller wave or no wave at all.
The type of interference that occurs depends on the relative amplitudes, wavelengths, and phases of the two waves.
Therefore, destructive interference takes place when the crest of one wave passes through the trough of another wave.
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what is the efficiency of a machine that can carry a load of 100 kg with an effort of 20N when its velicity ratio is 10 ASAP
Answer:
Efficiency of machine=4.9
Explanation:
We are given that
Mass of load=100 kg
Effort=20 N
Velocity ratio=10
We have to find the efficiency of machine.
Load=[tex]mg=100\times 9.8=980 N[/tex]
Efficiency=[tex]\frac{Load}{effort}\times \frac{1}{velocity\;ratio}[/tex]
Using the formula
Efficiency of machine=[tex]\frac{980}{20}\times \frac{1}{10}[/tex]
Efficiency of machine=[tex]\frac{49}{10}[/tex]
Efficiency of machine=4.9
What is true about the force between charges?
Explanation:
The force between two charges is given by :
[tex]F=\dfrac{kq_1q_2}{r^2}[/tex]
k is electrostatic constant
r is distance between charges
The force between charges is directly proportional to the product of charges and inversely proportional to the square of the distance between them.
When only ________ acts on an object's mechanical energy is conserved.
A.) Gravity
B.) Friction
C.) Air resistance
D.) Momentum
help ASAP
Answer:
Gravity
Explanation:
A 4-ohm and 2-ohm resistor are wired in PARRELL. What is the TOTAL resistance?
Answer:
1.33ohms
Explanation: The formula for resistance in a parallel circuit is :
1/Rt = 1/R1+1/R2
Where Rt represents total resistance, R1 = 4ohms and R2 = 2ohms
1/Rt = 1/4+1/2
1/Rt = 1+2/4
1/Rt = 3/4
Rt = 4/3
Rt= 1.33ohms
Hence the total resistance is 1.33ohms
What happens to energy “lost” during an energy transformation? A. It turns into heat energy. B. It turns into kinetic energy. C. It turns into potential energy. D. It turns into kinetic energy and potential energy.
Answer:
I think it turns into heat (thermal) energy if I'm right
as the trait is dominant and controlled by a single gene,the mutation must have occurred on both diploid copies. true or false?
Answer:
False
Explanation:
A dominant trait is a trait that is inherited from parents. It is a trait that is obtained from a particular copy or type of a gene that overshadows or overwhelms the effects of another type or copy of that gene. Dominant traits are controlled by a single gene.
Therefore , as the trait is dominant and controlled by a single gene,the mutation must have occurred on both diploid copies is a false statement.
6. A technlclan can be electrocuted when working on HEVs or EVs.
A) O True
B) O False
Answer:
True
Explanation:
It is true that. A technician can be electrocuted when working on HEVs or EVs, therefore the correct answer is option A
What is an electric vehicle (EV)?An EV stands for an electric vehicle. Electric vehicles (EVs) are autos that are powered totally or partially by electricity. Electric cars are extremely cost-effective to run because they have fewer moving parts to maintain and use little to no fossil fuels (petrol or diesel).
When evaluating its environmental impact, every factor must be taken into consideration. Considering that EVs have a minimal overall environmental impact, this suggests that the severity of these production emissions decreases.
Recycling is one strategy for lowering the lifespan emissions of electric vehicles. Again, incorrect assumptions can be refuted by facts.
Thus, That is accurate. The correct response is option A because a technician could electrocute themselves while working on HEVs or EVs.
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A steam power plant produces 50MW of net work while burning fuel to produce 150MW of heat energy at the high temperature. Determine the cycle thermal efficiency and the heat rejected by the cycle to the surroundings.
[tex]Nth[/tex] =[tex]\frac{W net, out}{Qh}[/tex]
50MW is our net output.
Then, we plug it in.
= [tex]\frac{50MW}{150MW}[/tex] = 0.333 or 33.33%
W net, out = Qh - Ql
Ql = Qh - W net,out
Plug the values in.
Then, it becomes:
= 150MW - 50 MW
= 100MW
Thus, the cycle thermal efficiency is 33.33% and the heat rejected is 100MW.
100 MW of the cycle thermal efficiency and the heat is thermal energy rejected by the cycle to the surroundings.
What is thermal energy?The energy present in a system that determines its temperature is referred to as thermal energy. Thermal energy flows as heat. Thermodynamics is a whole field of physics that studies how heat is transmitted across various systems and how work is performed in the process.
N = W/Q
50 MW is our net output.
Then, we plug it in.
= 50/150 = 0.333 or 33.33%
W net, out = Qh - Ql
Ql = Qh - W net,out
Plug the values in.
Then, it becomes:
= 150 MW - 50 MW
= 100 MW
Thus, the cycle thermal efficiency is 33.33% and the heat rejected is 100 MW
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which forces causes oppositely charged particles to attract each other?
Answer:
Electromagnetism causes like-charged objects to repel each other and oppositely charged objects to attract each other. The electromagnetic force binds negative electrons to the positive nuclei in atoms and underlies the interactions between atoms.
