A child, m = 25. 0 kg, swings from a rope, l = 9. 43 m, which hangs above water, d = 1. 9 m, when vertical. The child is h = 4. 8 m above the water when she begins to swing.
The velocity at the bottom of the swing is [tex]\mathbf{v= \sqrt{2gh -2gd}}[/tex]. The time it took the child to reach the river is 0.62 seconds.
The objective of this question is to determine:
The expression for the velocity of the child at the bottom of the swing.Suppose the child lets go at the bottom of the swing, how long does she take to reach the river at t seconds.At the bottom of the swing, there is an equal change in both the Kinetic energy as well as the potential energy and the expression can be computed as:
[tex]\mathbf{\dfrac{1}{2}mv^2 = mg (h -d)}[/tex]
[tex]\mathbf{\dfrac{v^2}{2}= g (h -d)}[/tex]
[tex]\mathbf{v^2= 2gh -2gd}[/tex]
[tex]\mathbf{v= \sqrt{2gh -2gd}}[/tex]
According to the second equation of motion;
[tex]\mathbf{S = ut +\dfrac{1}{2}at^2}[/tex]
where;
distance s = d = 1.9 macceleration due to gravity = 9.8 m/s²initial velocity (u) = 0∴
[tex]\mathbf{1.9 = 0(t) +\dfrac{1}{2}(9.8) t^2}[/tex]
[tex]\mathbf{1.9 = \dfrac{1}{2}(9.8) t^2}[/tex]
[tex]\mathbf{t^2 =\dfrac{1.9\times 2}{9.8} }}[/tex]
[tex]\mathbf{t = \sqrt{\dfrac{1.9\times2}{9.8}}}[/tex]
[tex]\mathbf{t =0.62 \ s}[/tex]
Therefore, we can conclude that the velocity at the bottom of the swing is [tex]\mathbf{v= \sqrt{2gh -2gd}}[/tex]. The time it took the child to reach the river is 0.62 seconds.
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Work is required to lift a barbell. How many times more work is required to lift the barbell 2 times as high
Answer:
2 time
Explanation:
when distance double the work double
help -----------------------------------------
Answer:
H,G,E,D,C,B,A,I,F
Explanation:
F is an ignious intrusion and I cross cuts H to A so it must be newer.
what do u guys think of my drawing?
Answer: yess sirrrrrrrr
Explanation:
Answer:
oou I like it! u did a good job ^^
A 25 kg chair initially at rest on a horizontal floor requires a 165 N horizontal force to set it in motion. Once the chair is in motion, a 127 N horizontal force keeps it moving at a constant velocity.
Find the coefficient of static friction between the chair and the floor.
b. Find the coefficient of kinetic friction between the chair and the floor.
a. The coefficient of static friction between the chair and the floor is 0.67.
b. The coefficient of kinetic friction between the chair and the floor is 0.52.
Given the following data:
Mass of chair = 25 kgHorizontal force A = 165 NHorizontal force B = 127 NScientific data:
Acceleration due to gravity = 9.8 [tex]m/s^2[/tex]a. To find the coefficient of static friction between the chair and the floor:
Mathematically, the force of static friction is given by the formula;
[tex]F_s = uF_n = umg[/tex]
Where;
Fs represents the force of static friction.μ represents the coefficient of static friction.[tex]F_n[/tex] represents the normal force.g is the acceleration due to gravity.mμ is the mass of an object.Making μ the subject of formula, we have:
[tex]u=\frac{F_s}{mg}[/tex]
Substituting the given parameters into the formula, we have;
[tex]u=\frac{165}{25 \times 9.8} \\\\u=\frac{165}{245}[/tex]
μ = 0.67
b. To find the coefficient of kinetic friction between the chair and the floor:
Note: The normal force would be the same as above.
[tex]u_k = \frac{F_k}{F_n} \\\\u_k = \frac{127}{245}\\\\u_k =0.52[/tex]
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2. Michael tells Sara he weighs 104 pounds. Sara says she is 44 kilograms. If there are 2.2
pounds in a kilogram, who is heavier?
Michael is heavier
Sara weighs= 44kg
Michael= 104 pounds which is equal to 47.174kg
THUS, micheal is heavier
Hope this helped you- have a good day bro cya)
How much force is required to move a tractor 60m, when using 250J of work?
Answer:
Work done,W= 250J
Displacement , s = 60
We know that, Work done = Force x displacement
i.e , W = Fxs
250 J = F x 60m
F = 250/60
=4.16 N
Hence , 4.16 N of Force is applied on the body.
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Acceration is a change in motion over time:
True False
A guitar string has a fundamental frequency f. The tension in the string is increased by 1.70%. Ignoring the very small stretch of the string. How does the fundamental frequency change?
The characteristics of the speed of the waves in strings and the resonance allows to find the change in the fundamental frequency when changing the tension is:
The change in fundamental frequency is: f = 1.08 f₀
The speed of the chord wave is given by the relationship between the tension and the density of the medium.
[tex]v= \sqrt{\frac{T}{\mu } }[/tex]
Where v is the velocity of the wave, T the tension of the string and μ the density
In a rope held at the ends, a process of standing waves occurs, two at the point where it is attached we have a node and a anti-node in the center.
2L = n λ
Where L is the length of the chord and call the wavelength
Wave speeds are related to wavelength and frequency.
v = λ f
We substitute.
[tex]\sqrt{\frac{T}{\mu } } = \frac{2L}{n} \ \ f[/tex]
For the fundamental frequency n = 1
f₀ = [tex]f_o = \sqrt{\frac{T}{\mu } } \ \ \frac{1}{2L}[/tex]
They indicate that the tension increases 1.70%
T = T₀ + 0.17 T₀
T = 1.17 T₀
We substitute.
[tex]f = \sqrt{1.17 } \ \sqrt{\frac{T_o}{\mu } } \ \ \frac{1}{2L}[/tex]
f = ra1.17 f₀
f = 1.08 f₀
In conclusion, using the characteristics of the velocity of the waves in strings and the resonance we can find the change in the fundamental frequency when changing the tension is:
The change in fundamental frequency is: f = 1.08 f₀Learn more about string resonance here: brainly.com/question/16010929
the free body diagram shown above is for a 5 kg box on a rough surface being pulled to the right at a constant speed by a string that is at an angle of 30° above the horizontal. the coefficient of kinetic friction between the box and the surface is 0.30. the tension in this string is most nearly:
The tension in the string pulling the box is most nearly 17 N.
The given parameters;
mass of the box, m = 5 kginclination of the string, θ = 30°coefficient of kinetic friction, μ = 0.3The tension on the string is calculated by applying Newton's second law of motion as follows.
[tex]\Sigma F = ma[/tex]
at constant speed, acceleration, a, = 0
[tex]\Sigma F = 0\\\\T_x - \mu F_n = 0\\\\Tcos(\theta) - \mu F_n = 0\\\\Tcos(\theta)= \mu F_n\\\\T = \frac{\mu F_n}{cos(\theta)} \\\\T = \frac{0.3 \times 5 \times 9.8}{cos(30)} \\\\T = 16.97 \ N\\\\T \approx 17 \ N[/tex]
Thus, the tension in the string pulling the box is most nearly 17 N.
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find the impulse of a 20.0 KG object accelerates to8.1 M/S from 2.3 M/S
Answer:
116 N•s
Explanation:
change in momentum = mvf-mvi
= m(Vf - Vi)
= 20( 8.1-2.3)
change in momentum= 116 kg•m/s
: .impulse is 116 N•s
NO LINKS! What are the definitions of initial horizontal velocity and initial vertical velocity? Please help! This like is my 10th time asking this question because many people have been scamming me.
Explanation:
Initial horizontal velocity
If a projectile is launched at an angle to the horizontal, then the initial velocity of the projectile has both a horizontal and a vertical component. The horizontal velocity component (vx) describes the influence of the velocity in displacing the projectile horizontally.
The initial horizontal velocity can also be determined by measuring the diameter d of the ball and dividing by the time t that it takes for the ball to move across the photogate. That is Vo = d/t.
Initial vertical velocity
Vertical velocity refers to the speed of an object's movement in a vertical direction.The initial vertical velocity is the vertical component of the initial velocity: v 0 y = v 0 sin θ 0 = ( 30.0 m / s ) sin 45 ° = 21.2 m / s .
If Corolla does 1,800,000 Joules of work in a 400 meter race, how much average force was applied through that distance?
Answer:
4500 NExplanation:
The work done by an object can be found by using the formula
workdone = force × distance
To find the force applied we make force the subject in the formula above
That's
[tex]f = \frac{w}{d} \\ [/tex]
w is the workdone
d is the distance
From the question we have
[tex]f = \frac{1800000}{400} = \frac{18000}{4} = 4500\\ [/tex]
We have the final answer as
4500 NHope this helps you
c. How can you explain natural selection in evolution of insects from the time they evolved till our days now?
how many seconds does it take an object to fall 98m if it start from the rest .(using gravity 10m/s²?
Answer:
Neither.
Explanation:
After 10 seconds the object will have travelled 490.5m, not 98.1. The vertical distance covered in freefall by an object in time t is given by Distance= 1/2 x 9.81 x t^2. Simply multiplying 9.81 by the time will NOT give the distance covered.
The acceleration of the object will not change, it will always be 9.81 m/s^2. Its speed will keep increasing by 9.81 m/s every second, thats what the ‘per second squared*’ means. The speed after 10 seconds will be 98.1 m/s
To summarise, after 10 seconds, the object will have covered 490.5 metres, and it will have a final speed of 98.1 m/s. It’s acceleration will remain 9.81 m/s^2 at all times
what is the meaning of physics
Answer:
the branch of science concerned with the nature and properties of matter and energy. The subject matter of physics, distinguished from that of chemistry and biology, includes mechanics, heat, light and other radiation, sound, electricity, magnetism, and the structure of atoms.
Explanation:
How to calculate specific heat.
At about 1 second after the beginning of the universe, one type of particle was able to start traveling freely through the universe. These particles are still with us, but they are extremely hard to detect. They are called:
The Big Bang theory allows finding the result for which particles were formed in the 1 s of the universe is:
The quark subatomic particles were the first to form due to the high amount of energy.
The Big Bang theory says that the universe is formed about 14 billion years ago, of a structure that is very high energy.
Einstein's equation establishes the relationship between energy and matter, establishing that energy can be converted into matter.
E = m c²
Where E is energy, m is mass, and c is the speed of light.
In the 1 s of the universe the energy density was so high that all subatomic particles were formed, the first being quarks.
When the universe cooled enough, the quarks combined to form protons and neutrons, from which atoms were formed.
In conclusion, using the Big Bang theory we can find the result for which particles were formed in the 1 s of the universe is:
The quark subatomic particles were the first to form due to the high amount of energy.
Learn more about the Big Bang here: brainly.com/question/3333508
How much physical activity should an adult have each week?
A.
60 minutes per day, 7 days a week
B.
30 minutes per day, 7 days a week
C.
60 minutes per day, 5 days a week
D.
30 minutes per day, 5 days a week
Please select the best answer from the choices provided.
A
B
C
D
The physical activity should an adult have each week is "60 minutes per day, 5 days a week". The correct answer is option C.
What is WHO?WHO stands for the World Health Organization. It is a specialized agency of the United Nations responsible for international public health. The WHO is headquartered in Geneva, Switzerland, and works in partnership with national governments and other organizations to promote health, keep the world safe, and serve the vulnerable. The organization's primary objective is to ensure that people can enjoy the highest possible level of health, regardless of their race, religion, or socioeconomic status. The WHO's work includes providing leadership on matters critical to health, setting norms and standards, promoting health research and evidence-based practice, and providing technical support to countries.
Here in the Question,
Option A, "60 minutes per day, 7 days a week," and option B, "30 minutes per day, 7 days a week," both suggest that physical activity should be performed every day of the week. While daily physical activity is beneficial for overall health and well-being, the WHO recommendation allows for two days of rest or lighter physical activity per week, which can help prevent injury and allow for recovery.
Option D, "30 minutes per day, 5 days a week," suggests a lower amount of physical activity than the WHO recommendation. While 30 minutes of moderate-intensity aerobic physical activity per day can provide some health benefits, it may not be enough to achieve significant improvements in cardiovascular health, muscular strength, and flexibility.
Therefore, Option C, "60 minutes per day, 5 days a week," is the correct answer as it aligns with the WHO recommendation for adults to engage in at least 150 minutes of moderate-intensity aerobic physical activity per week.
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2. If Joe rides his bicycle in a straight line for 15 min with an average velocity of 12.5 km/h south, how far has he ridden?
Answer:
3.125 Kilometers
Explanation:
To answer this you just multiply 12.5 by .25 (since 15 minutes is a quarter of an hour) to get 3.125 kilometers ridden.
Please answer correctly.
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what is Secular Music's instrument's?
Answer:
Drums, harps, recorders, and bagpipes.
Explanation:
a race car traveling at 44m/s slows at a constant rate to a velocity of 22m/s over 11 seconds , how far does it move during this time
find distance and acceleration
FAST PLEASE !!
Answer:
-1.2×10^2 m
I hope this helps you
Waves can be refracted.
Explain this term.
HELP PLSSS
Answer: By "waves can be refracted" they mean that refraction can occur with waves. To better explain, refraction is the "change in direction of a wave passing from one medium to another or from a gradual change in the medium." You probably know this best when you put a pencil inside a glass of water where the pencil bends a bit. The same can happen with sound or water waves as well!
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BEFORE COLLISION
MASS = 4200 kg
MASS = 990 kg
V = 10 m/s
AFTER COLLISION
V = ?
V = 2 m/s
What is the velocity after the crash?
Initial kinetic energy KE = 1/2 m1v12 + 1/2 m2v22 = joules. The following calculation expects you to enter a final velocity for mass m1 and then it calculates the final velocity of the other mass required to conserve momentum and calculates the kinetic energy either gained or lost to make possible such a collision.
Please give an answer that is coherent
A ceiling fan operates at three speeds, using 120 V of electricity from the wall. At low speeds, it uses 0.25 A. Calculate the resistance needed to generate that current. Then in 1-2 sentences, describe how the resistance would change at medium and high speeds if larger currents are needed at those speeds. Your answer should include the calculated resistance and a sentence describing your reasoning.
Answer:
480
Explanation:
resistance equals to potential difference divide by electric current
120÷0.25
=480
Answer:
[tex]\mathsf {480 \Omega}[/tex]
Explanation:
[tex]\textsf {Formula used for calculating resistance :}[/tex]
[tex]\mathsf {Resistance = \frac{Voltage}{Current} }[/tex]
[tex]\textsf {This is otherwise known as Ohm's Law, hence the unit of resistance.}\\[/tex]
[tex]\textsf {Solving :}[/tex]
[tex]\implies \mathsf {R = \frac{120}{0.25}}[/tex]
[tex]\implies \mathsf {R = 480\Omega}[/tex]
[tex]\textsf{If the fan uses higher current at higher speeds, then}\\\textsf{the resistance would decrease as it is inversely}\\\textsf {proportional to the current.}[/tex]
please help I'm stuck on this question
Answer:
increase
decrease
Explanation:
using formula
Vt=mg/6πηr
so if m increases V increases
r is the denominator so if r increases V decreases
Plz help ⭐..................
Answer:
where in the world is the image????..
The high energy yields created by nuclear fission are due to
A. Binding nuclei
B. Chain reactions
C. Hydrogen bonding
D. Secondary recovery
Answer:
Nuclear fission of heavy elements produces exploitable energy because the specific binding energy (binding energy per mass) of intermediate-mass nuclei with atomic numbers and atomic masses.
Explanation:
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which type of telescope is best used to detect quasars?
Answer:Gamma-Ray Telescopes
Explanation:
Gamma-Ray Telescopes are used for detecting the gamma-ray part of the Electromagnetic Spectrum. These can detect very high-energy gamma-rays from radio galaxies, gamma-ray bursts from stars, supernovae events, and Quasars.
Radio Waves Telescope
