Explanation:
The unit called decibel (dB) is used to indicate that this ratio is multiplied by 10. The sound intensity level is not the same as sound intensity—it tells you the level of the sound relative to a reference intensity rather than the actual intensity.
A 27 kg disk with a radius of 1.3m is spinning at an angular speed of 15 rad/s. What is the rotational kinetic energy of the disk?
Answer:
the rotational kinetic energy of the disk is 5,133.375 J
Explanation:
Given;
mass of the disk, m = 27 kg
radius of the disk, r = 1.3 m
angular speed, ω = 15 rad/s
The rotational kinetic energy of the disk is calculated as;
[tex]K.E_{rot} = \frac{1}{2}I \omega^2\\\\ where;\\I \ is \ moment \ of \ inertia\\\\K.E_{rot} = \frac{1}{2} \times (mr^2) \times \omega ^2\\\\ K.E_{rot} = \frac{1}{2} \times (27\times 1.3^2) \times \ 15^2\\\\K.E_{rot} = 5,133.375 \ J[/tex]
Therefore, the rotational kinetic energy of the disk is 5,133.375 J
If the distance between the source of sound and observer is reduced to one half, then
the intensity of sound will become
Answer:
Let the power delivered by the sound wave be 'P'
Intensity by definition is the power delivered per unit area.
i.e. I =
dA
dP
;
In spherical polar coordinate system dA = r
2
Ω
I =
r
2
Ω
dP
;
I ∝
r
2
1
So if distance increases 3 fold. The Intensity becomes
9
1
times the initial
What is a sound wave?
The wind blows a leaf at 37.9 m/s for 118 s left. How are does the leaf go in that period of time.
A) 3.11 m, left
B) 4470 m, left
C) 80.1 m, left
D) 0.321 m, left
Explanation:
distance = velocity * time
d = 37.9 * 118
distance = 4472.2
Do solar panels create enough energy to power the car throughout the day?
Answer:
Yes, but only if it's sunny.
Explanation:
As you know, solar panels generate energy through the sun's rays of light (better known as sunlight). Therefore, as long as the sun is shining high in the sky, the car will generate electricity and be able to function. If this vehicle was only powered by solar panels, it would not function during the night, in cloudy areas, and/or in dark places (such as parking garages or home garages).
Hope this helps!
Croquet balls must have a mass of 0.50 kg. A red croquet ball is moving at 5 m/s. It strikes an at-rest green croquet ball head-on and then continues to move in the same direction, but with a speed of 2 m/s. What is the final speed of the green ball?
A.
5 m/s
B.
0.5 m/s
C.
2 m/s
D.
3 m/s
Answer:
Explanation:
The Law of Momentum Conservation for us has the equation
[tex][m_rv_r+m_gv_g]_b=[m_rv_r+m_gv_g]_a[/tex] and filling in:
[tex][(.50)(5.0)+(.50)(0)]=[(.50)(2.0)+(.50)v_g][/tex] and
2.5 = 1.0 + .50v and
1.5 = .50v so
v = 3 m/s
The final speed of the green ball is 3m/s. This can be calculated by the law of conservation of momentum. Thus, the correct option is D.
What is the law of Conservation of Momentum?
The principle of the law of conservation of momentum states that if any two objects undergo collision, then the total momentum of the objects before and after the collision will be the same if there is no external force acting on the colliding objects.
The Law of Conservation of Momentum has the equation which is:
m₁ × u₁ + m₂ × u₂ = m₁ × v₁ + m₂ × v₂
where, m₁ = mass of object 1,
u₁ = initial velocity of object 1 before collision,
m₂ = mass of object 2,
v₁ = final velocity of object 1 after collision,
v₂ = final velocity of the object 2 after collision.
0.50 × 5 + 0.50 × 0 = 0.50 × 2 + 0.50 × v₂
2.5 + 0 = 1.0 + 0.50 × v₂
2.5 - 1.0 = 0.50 × v₂
1.5 = 0.50 × v₂
1.5/ 0.5 = v₂
v₂ = 3m/s
Therefore, the correct option is D.
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Felipe drives his car at a velocity of 28 m/s. He applies the brake, which slows the vehicle down at a rate of 6.4 m/s2 and causes it to slow to a stop. How long does it take for the car to stop? Round your answer to the nearest tenth.
Answer:
Explanation:
Use the one-dimensional equation
[tex]v_f=v_0+at[/tex] where v is the final velocity, v0 is the initial velocity, a is the acceleration, and t is the time it takes to reach that final velocity. We are solving for t. Filling in the other values:
0 = 28 + (-6.4)t and
-28 = -6.4t so
t = 4.4 seconds
Answer:
4.4
Explanation:
Que capacidade física consiste em deslocar o corpo no espaço o mais rápido possível, mudando o centro de gravidade de posição, sem perder o equilíbrio e a coordenação dos movimentos?
Answer:ur mom
Explanation:because
When a golfer tees off, the head of her golf club which has a mass of 151 g is traveling 43.9 m/s just before it strikes a 46.0 g golf ball at rest on a tee. Immediately after the collision, the club head continues to travel in the same direction but at a reduced speed of 28.2 m/s. Neglect the mass of the club handle and determine the speed of the golf ball just after impact
Answer:
51.54 m/s
Explanation:
Applying,
Law of conservation of momentum,
Total momentum before collision = Total momentum after collision
mu+m'u' = mv+m'v'.................... Equation 1
Where m = mass of the head of the golf club, m' = mass of the gulf ball, u = initial velocity of the head of the gulf club, u' = initial velocity of the gulf ball, v = final velocity of the head of a gulf club, v' = final velocity of the gulf ball
From the question,
Given: m = 151 g = 0.151 kg, u = 43.9 m/s, m' = 46 g = 0.046 kg, u' = 0 m/s (at rest), v = 28.2 m/s
Substitute these values into equation 1
0.151(43.9)+0.046(0) = 0.151(28.2)+0.046(v')
solve for v'
6.6289+0 = 4.2582+0.046v'
0.046v' = 6.6289-4.2582
0.046v' = 2.3707
v' = 2.3707/0.046
v' = 51.54 m/s
A small hole is made at the bottom of a plastic cup. If it is filled with water and allowed to fall freely, will waterfall down from the hole?
Answer:
It depends on how big the hole is.
Explanation:
If the hole is too big, the water will fall freely out of the cup. However, if it is just a small opening (from a needle, pencil/pen tip, etc.) the water pressure will be able to hold in the water.
How efficient is a pulley system if an operator has to pull 2.5m of rope to lift a 250 N pail of water a distance of 4.5 m?
Answer:
the pulley system is very efficient
Explanation:
Given;
load, L = 250 N
distance moved by the load, a = 4.5 m
distance moved by the effort, e = 2.5 m
let the force or effort applied = F
Apply the principle of conservation of energy;
F x e = L x a
F = (L x a) / e
F = (250 x 4.5) / 2.5
F = 450 N
The efficient of the pulley system;
E = Output force / Input force
E = (450 x 2.5) / (250 x 4.5)
E = 1 = 100%
Therefore, the pulley system is very efficient
A spring has an unstretched length of 0.2 m. A 0.2 kg mass hanging from the spring stretches it to an equilibrium length of 0.3 m. Suppose the mass is pulled down to where the spring’s length is 0.5 m. When it is released, it begins
to oscillate. What is the amplitude of the oscillation?
an object of volume 1m3 and density of 500kg/m3 float in water what volume of water is displaced
Answer:
[tex]0.5\; \rm m^{3}[/tex].
Explanation:
Calculate the mass of this object:
[tex]\begin{aligned}& m(\text{object}) \\ &= \rho(\text{object}) \cdot V(\text{object}) \\ &= 500\; \rm kg \cdot m^{-3} \times 1\; \rm m^{3} = 500\; \rm kg\end{aligned}[/tex].
Multiple the mass of this object by the gravitational field strength, [tex]g[/tex], to find the weight of this object: [tex]W(\text{object}) = m(\text{object}) \cdot g[/tex].
Since this object is floating in water, the buoyancy force on it should be equal to its weight:
[tex]F(\text{buoyancy}) = W(\text{object}) = m(\text{object}) \cdot g[/tex].
By Archimedes' Principle, the weight of the water that this object displaces would be equal to [tex]F(\text{buoyancy})[/tex], the size of buoyancy force on this object,
Hence, the weight of water displaced would be [tex]W(\text{object}) = m(\text{object}) \cdot g[/tex].
Divide this weight by [tex]g[/tex] to find the mass of water displaced:
[tex]\begin{aligned} & m(\text{water displaced}) \\ &= \frac{W(\text{water displaced})}{g} \\ &= \frac{m(\text{object}) \cdot g}{g} = m(\text{object}) = 500\; \rm kg\end{aligned}[/tex].
Assume that the density of water is [tex]\rho(\text{water}) = 1000\; \rm kg \cdot m^{-3}[/tex]. The volume of water displaced would be:
[tex]\begin{aligned}& V(\text{water displaced}) \\ &= \frac{m(\text{water displaced})}{\rho(\text{water})} \\ &= \frac{500\; \rm kg}{1000\; \rm kg \cdot m^{-3}} = 0.5\; \rm m^{3}\end{aligned}[/tex].
Which best describes the energy of a sound wave as it travels through a medium? It increases. It decreases. It remains the same. It depends on the medium.
Answer:
It depends on the medium
Explanation:
2021 edge
The energy of a sound wave decreases as it travels through a medium to another medium. Thus, the correct option is D.
What is a Sound wave?A sound wave is the pattern of disturbance which is caused by the energy which is travelling away from the source of the sound in that medium. Sound waves are the longitudinal waves. This means that the propagation of these vibration of particles is parallel to the energy which this wave propagation direction has. When the atoms in the medium are set in vibration then they move back and forth in a direction. This continuous to occur in back and forth motion resulting in a high-pressure and a low-pressure region in the medium and thus propagating sound.
Sound wave is the physical vibration wave which travel through the air to reach the ears of organisms. Sound energy is the result when force makes an object to vibrate. A wave can lose energy as it travels through a medium because the medium can also absorb the energy from the wave. The medium changes some of the acoustic energy of the sound wave into heat energy.
Therefore, the correct option is D.
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Which force determines if an object is going to move or stay at rest?
a. Friction Force
b. Normal Force
c. Applied Force
d. Net Force
Answer:
a
Explanation:
because it's need someone moving it so it can move somewhere else
If a 2.0Ω resistor and a 4.0Ω resistor are connected with a 12 volt battery, what is the total resistance of the circuit?
4.8Ω
9.2Ω
6.0Ω
1.3Ω
A ball is rolling along a straight and level path. The ball is traveling at a constant speed of 2.0 m/s. The mass of the ball is 3.0 kg. What is the kinetic energy of the ball?
A. 6.0 J
B. 9.0 J
C. 12.0 J
D. 3.0 J
hmkjiji8gjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjjj
Cuatro contenedores idénticos tienen la misma cantidad de gas helio a la misma temperatura inicial. Los recipientes también cuentan con un émbolo móvil que no permite que el helio escape. Cada muestra de gas sigue un proceso distinto como se describe a continuación: Muestra 1: 500 J de calor salen del gas y este realiza 300 J de trabajo. Muestra 2: 500 J de calor entran al gas y este realiza 300 J de trabajo. Muestra 3: 500 J de calor salen del gas y se hace un trabajo de 300 J sobre él. Muestra 4: 500 J de calor entran al gas y se hace un trabajo de 300 J sobre él.
Answer:
1) ΔE = -800 J, 2) ΔE = 200 J, 3) ΔE = -200 J, 4) ΔE = 800 J
Explanation:
For this exercise let's use the first law of thermodynamics
ΔE = Q + W
Where we will apply this expression to several cases
1) output Q = 500 J and does work of W = 300 J.
The two processes involve an energy output
ΔE = - 500 - 300
ΔE = -800 J
Therefore, the internal energy of the gas decreases by this amount,
2) enter Q = 500J and do work of W = 300 J
Positive heat is added and does negative work
ΔE = 500 - 300
ΔE = 200 J
3) they leave Q = 500 J and do (work on the gas) W = 300J
negative heat and positive work come out
ΔE = -500 + 300
ΔE = -200 J
4) heat enters Q = 500 J, work on gas W = 300 J
both positive
ΔE = 500 + 300
ΔE = 800 J
the value of 'g' changes as per its position on the earth's surface.justify the statement
Answer:
PLEASE MARK ME AS A BRAINLIEST
Explanation:
There are slight variations in the value of g about earth's surface. These variations result from the varying density of the geologic structures below each specific surface location. They also result from the fact that the earth is not truly spherical; the earth's surface is further from its center at the equator than it is at the poles. This would result in larger g values at the poles. As one proceeds further from earth's surface - say into a location of orbit about the earth - the value of g changes still.
a que velocidad en km/h corrio usain bolt en el capeonato mundial de berlin en 2009 para batir el record mundial de los 100 m planos en 9.58
Answer:
v = 37.59 km/h
Explanation:
The question says, "how fast in km / h did usain bolt run at the berlin world championship in 2009 to break the world record for the 100m sprint in 9.58".
Distance, d = 100 m = 0.1 km
Time, t = 9.58 s = 0.00266 h
We need to find the speed of the Usain Bolt. We know that,
Speed = distance/time
So,
[tex]v=\dfrac{0.1}{0.00266}\\\\v=37.59\ km/h[/tex]
So, the required speed is equal to 37.59 km/h.
A man who weighs 75kg on the surface of the earth whose mass is 6*10^24kg. If the radius of earth is 6480km ,calculate the force of attraction between them.
Answer:
718.02N is the answer to the question
Which of the following describes the work done by a heat engine?
A. Qin - Qout
B. Qin - W
C. Qout - Qin D. Qin + Qout
Answer: A.
Explanation:
Máquina térmica tem como função, manter a temperatura de um dado fluído, então, a quantidade de calor desse mesmo fluído ao entrar na máquina, será igual á quantidade de calor desse fluido saindo.
Qin - Qout describes the work done by a heat engine. Hence option A is correct.
What is heat engine ?A heat engine is a system which converts heat into useful work. Carnot engine is an ideal engine which has maximum efficiency than any other engines. Carnot has showed that "no engine can be more efficient than Carnot engine and the 100% efficient engine can not be existed". It takes heat from the reservoir to do some work and it discharges some amount of heat to the sink. Reservoir is know as hot body and sink is know as cold body.
Efficiency of the Carnot's heat engine is given by,
Efficiency, η = Work done / Heat input
Work done, W = Q1 – Q2
Heat input = Q1
Efficiency,
η = W / Q1
= (Q1 – Q2) / Q1
=1 – (Q2 / Q1).
To have engine with 100% efficiency, Q2 must be zero and it is not possible.
Hence work done by a heat engine is Qin - Qout.
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When do we say that work is done?
Answer:
Work is said to be done when a force applied to an object moves that object. We can calculate work by multiplying the force by the movement of the object.
Answer:
Work is done by a force on an object if (i) a force acts on the object and (ii) the object is displaced from its original position
A hydrometer is an instrument used to determine liquid density. A simple one is sketched in the figure below. The bulb of a syringe is squeezed and released to lift a sample of the liquid of interest into a tube containing a calibrated rod of known density. (Assume the rod is cylindrical.) The rod, of length L and average density 0, floats partially immersed in the liquid of density . A length h of the rod protrudes above the surface of the liquid. Show that the density of the liquid is given by
=
0L
L − h
.
(Do this on paper. Your instructor may ask you to turn in this work.)
Answer:
weight of rod =weight of liquid displaced
mass of the rod ×g =mass of liquid displaced ×g
(g cancelled out)
mass of the rod =mass of liquid displaced
density of rod ×volume of rod =density of liqiud ×volume of liquid displaced
O×cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface
O×L=density of liquid ×(L-h)
then density of liquid =OL/(L-h) shown as required
The density of the liquid is given by =OL/L − h
What is density?Density is the ratio of mass of an object and its volume.
According to the Archimedes principle, weight of rod = weight of liquid displaced
mass of the rod ×g =mass of liquid displaced ×g
So, mass of the rod =mass of liquid displaced
Mass in terms of density is substituted,
density of rod × volume of rod =density of liquid ×volume of liquid displaced
O× cross section area of rod ×height of rod =density of liquid ×Cross section area of rod ×height of rod under the surface
O×L=density of liquid ×(L-h)
Then, density of liquid =OL/(L-h).
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Dad, if you are seeing this, then I have run away. Angie has been torturing me ever since you started dating her, and I have had enough of it. I have been trying to tell you, but you would never listen. Goodbye, and Angie, if you are seeing this, I posted this on here, so you will not be able to delete anything. Have a nice life
Answer:
hey are you ok!?!?!?!
Explanation:
Is Angie your Dad new gf or wife???
Answer:
:(
Explanation:
u ok?
running away from problems only makes things worse. Your teaching urself to run. but I dont blame u
anyway hope u find what ur looking for out there!!
which factor is least likely to limit the rate of photosynthesis?
- carbon dioxide concentration
- light intensity
- oxygen concentration
- temperature
Answer:
oxygen concentration
Explanation:
A piece of glass has mass of 1 kg and a density of 800 kgm-³ negative cubed calculate its volume
Explanation:
we know that
v = m/d
or; v=1kg/800kgm^3
or; v=0. 00125m
If you want to decrease the current created by a generator what can you do?
Answer:
To decrease the current;
1) Use fewer loops or number of turns
2) Use a lower speed of rotation of the coil in the magnetic field
3) Use a weaker magnetic
Explanation:
According to Faraday's Law of induction, which is the basis of the electromagnetism, electromagnetic induction and therefore the basis of the electric generator, can be written as follows;
[tex]\epsilon = -N \cdot \dfrac{\Delta \phi}{\Delta t}[/tex]
Where;
ε = The induced voltage
N = The number of turns (loops)
ΔФ = The change in the magnetic flux
Δt = The change in the time (the duration)
Given that voltage is directly related to the current, decreasing the voltage, decreases the current
To decrease the voltage, and therefore, the current we can;
1) Reduce the number of loops in the coil
2) Increase the time change per unit change in flux by slowing down the speed of rotation of the generator
3) Decrease the amount of change in the magnetic field per turn, by using a weaker magnetic
A train starting from rest moves with a uniform acceleration of 0.2 ms-2 for 5 minutes. Calculate the final velocity and the distance travelled in this time.
Answer:
Final velocity = 60 m/s
Distance travelled = 9000 m
Explanation:
Applying,
For Final velocity,
v = u+at ............... Equation 1
Where v = final velocity, u = initial velocity, a = acceleration, t = time.
From the question,
Given: u = 0 m/s(at rest), a = 0.2 m/s², t = 5 minutes = (5×60) = 300 s
Substitute these values into equation 1
v = 0+0.2(300)
v = 60 m/s.
Also for distance,
Applying,
s = ut+1/2at²................ Equation 2
Where s = distance travelled.
subtitute thes values above into equation 2
s = (0×300)+(0.2×300²)/2
s = 9000 m
