Answer:
The mystery that Greene discusses is that dark energy is causing the expansion of the universe to accelerate. However, this cannot be explained by the laws of Physics.
Explanation:
I majored in Physics
If a wave has a speed of 1000 m/s and frequency of 500 Hz, what is the wavelength?
• 1500 Hz
• 2 m
• 0.05 m
Answer:
2 m
Explanation:
speed=frequency×wavelength
wavelength=speed/frequency
wavelength=1000/500
=2 m
A mole of a monatomic ideal gas at point 1 (101 kPa, 5 L) is expanded adiabatically until the volume is doubled at point 2. Then it is cooled isochorically until the pressure is 20 kPa at point 3. The gas is now compressed isothermally until its volume is back to 5 L (point 4). Finally, the gas is heated isochorically to return to point 1.
a. Draw the four processes and label the points in the pV plane.
b. Calculate the work done going from 1 to 2.
c. Calculate the pressure and temperature at point 2.
d. Calculate the temperature at point 3.
e. Calculate the temperature and pressure and point 4.
f. Calculate the work done going from from 3 to 4.
g. Calculate the heat flow into the gas going from 3 to 4. g
Answer:
(a). Check attachment.
(b). 280.305 J.
(c). 31.81 kpa; 38.26K.
(d). 24.05K.
(e). 24.05k; 40kpa.
(f). -138.6J.
Explanation:
(a). Kindly check the attached picture for the diagram showing the four process.
1 - 2 = adiabatic expansion process.
2 - 3 = Isochoric process.
3 - 4 = isothermal process.
4 - 1 = isochoric process.
(b). Recall that the process from 1 to is an adiabatic expansion process.
NB: b = 5/3 for a monoatomic gas.
Then, the workdone = (1/ 1 - 1.66) [ (p1 × v1^b)/ v2^b × v2 - (p1 × v1)].
= ( 1/ 1 - 5/3) [ (101 × 5^5/3) × 10^1 -5/3] - 101 × 5.
Thus, the workdone = 280.305 J.
(c). P2 = P1 × V1^b/ V2^b = 101 × 5^5/3/ 10^5/3 = 31.81 kpa.
T2 = P2 × V2/ R × 1 = 31.81 × 10/ 8.324 = 38.36k.
(d). The process 2 - 3 is an Isochoric process, then;
T3 = T2/P2 × P3 = 38.26/ 31.82 × 20 = 24.05K.
(e). The process 3 - 4 Is an isothermal process. Then, the temperature at 4 will be the same temperature at 3. Tus, we have the temperature; point 3 = point 4 = 24.05k.
The pressure can be determine as below;
P4 = P3 × V3/ V4 = 20 × 10/ 5 = 200/ 5 = 40 kpa.
(f) workdone = xRT ln( v4/v3) = 1 × 8.314 × 24.05 × ln (5/10) = - 138.6 J
Two train whistles have identical frequencies of 180 Hz. When one train is at rest in the station and the other is moving nearby, a commuter standing on the train platform hears beats with a frequency of 2.00 beats/s when the whistles sound at the same time. What are the two possible speeds and directions that the moving train can have?
Actual answers :3.85 m/s away from the station and 3.77 m/s towards the station from the book. I just need to know how to get to the answers.
Answer:
-3.77 m/s
3.85 m/s
Explanation:
given that
Frequency at stationary = 180 Hz
Beat frequency = 2 Hz
Using Doppler effect, we know that
f' = f[(v ± v0) / (v ± vs)], where
v = speed of sound, 343 m/s
v0 = speed of the observer, 0
vs = speed of light, ?
f = stationary frequency, 180 Hz
f' = stationary ± beat frequency, 180 ± 2
Applying the formula, we have
f' = f[(v ± v0) / (v ± vs)]
182 = 180 [(343 + 0) / (343 + vs)]
182/180 = 343 / 343 + vs
343 + vs = 343 * 180/182
343 + vs = 339.23
vs = 339.23 - 343
vs = -3.77 m/s
Again, using
f' = f[(v ± v0) / (v ± vs)]
178 = 180 [(343 + 0) / (343 + vs)]
178/180 = 343 / 343 + vs
343 + vs = 343 * 180/178
343+ vs = 346.85
vs = 346.85 - 343
vs = 3.85 m/s
A vertical wire carries a current straight up in a region of the magnetic field directed north. What is the direction of the magnetic force on the current due to the magnetic field
Answer:
The direction of the force on the vertical wire is towards the East or right.
Explanation:
Using Fleming's right hand rule, the current is the middle finger pointing straight up, the magnetic field is the fore-finger pointing Northwards and then the thumb is the direction of the force on the vertical wire.
Following these conventions, the thumb points towards the East. So, the direction of the force on the vertical wire is towards the East or right.
How can you tell whether an object is neutral
or charged? What would you have to do to test
that object?
Answer:
The number of electrons that surround the nucleus will determine whether or not it is electrically charged or electrically neutral
Explanation:
A child holds a sled at rest on frictionless snow covered hill. if the sled weighs 77N,find the force T exerted by the rope on the sled and the force n exerted by the hill on the sled
Answer:62
Explanation:
The weight of the sled is 77 N. The force by the hill on the sled is equal to its weight that is 77 N. Then the tension force exerted by the rope on the sled is being 77N sin θ, where θ be the angle of inclination.
What is force?Force is an external agent acting on an object to change its motion or to deform it. There are various kinds of force like magnetic force, tension force, frictional force, gravitational force etc.
The weight that an object experience on earth is due to the gravitational force. The force that is exerted by a rope on an object is tension force since it is pulling from a side.
The normal force by the hill on the sled is equal to its weight that is 77 N. The tension force on the sled by the rope is dependent on the angle of inclination θ. If know the angle we can find T by the equation:
T = 77 sin θ.
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Which of the following describes the products of a chemical reaction?
A. The original materials
B. The substances that are changed
C. The chemicals on the left side of a chemical equation
Ο Ο
D. The chemicals on the right side of a chemical equation
Answer:
D The chemicals on the right side of a chamical equation
In a physics lab experiment for the determination of moment of inertia, a team weighs an object and finds a mass of 2.15 kg. They then hang the object on a pivot located 0.163 m from the object's center of mass and set it swinging at a small amplitude. As two of the team members carefully count 113 cycles of oscillation, the third member measures a duration of 241 s. What is the moment of inertia of the object with respect to its center of mass about an axis parallel to the pivot axis
Answer:
0.339 kgm²
Explanation:
We know the period of this pendulum, T = 2π√(I/mgh) where I = moment of inertia of the object about the pivot axis, m = mass of object = 2.15 kg, g = acceleration due to gravity = 9.8 m/s² and h = distance of center of mass of object from pivot point = 0.163 m.
Since T = 2π√(I/mgh), making I subject of the formula, we have
I = mghT²/4π²
Now since it takes 241 s to complete 113 cycles, then it takes 241 s/113 cycles to complete one cycle.
So, T = 241 s/113 = 2.133 s
So, Substituting the values of the variables into I, we have
I = mghT²/4π²
I = 2.15 kg × 9.8 m/s² × 0.163 m × (2.133 s)²/4π²
I = 15.63/4π² kgm²
I = 0.396 kgm²
Now from the parallel axis theorem, I = I' + mh² where I' = moment of inertia of object with respect to its center of mass about an axis parallel to the pivot axis
I' = I - mh²
I' = 0.396 kgm² - 2.15 kg × (0.163 m)²
I' = 0.396 kgm² - 0.057 kgm²
I' = 0.339 kgm²
Tyler and Jim race each other up a mountain on their bicycles. Tyler rides a road bike on the switchbacks of the twisting and turning mountain road. Jim rides a mountain bike and follows a direct, but steeper, straight-line path up the mountain. They start at the same time and place at the bottom of the mountain and finish at the same time and place at the top of the mountain. From start to finish a. whose distance traveled was longer? b. whose displacement was longer? c. which rider had the faster average speed? d. which rider had the faster average velocity? e. who won the race?
Answer:
Explanation:
Displacement is minimum distance between initial and final point .
Distance is total length of path covered in a journey .
a )
Tyler covered a longer distance in the journey because total length of path covered by him is longer due to curved path .
b )
Both have same displacement , because minimum distance between initial and final point in both the case is same .
c )
average speed = distance / time
as time is same for both the case ,
average speed ∝ distance
As distance covered by Tyler is more , his average speed is more .
d )
average velocity = displacement / time
As both displacement and time are same in both the case , average velocity in both the case is same .
e )
They start at the same time and place at the bottom of the mountain and finish at the same time , both have tie and nobody won the race , in spite of speed of Tyler being greater .
A bicyclist accelerates from rest to a speed of
5.0 meters per second in 10 seconds. During the
same 10 seconds, a car accelerates from a speed
of 22 meters per second to a speed of 27 meters
per second. Compared to the acceleration of the
bicycle, the acceleration of the car is
Answer:
They have the same acceleration of 0.5m/s2 (please note m/s2 is the unit for acceleration and 2 is the power of s)
Explanation:
acceleration= velocity ÷ time
and the time is said to be 10seconds
velocity of car will be the new velocity- the initial velocity = 27-22= 5
acceleration= 5÷10
acceleration= 0.5
hope this helped
now hit that crown button :)
What are two things that happen to the sugars that are made by the plant during photosynthesis?
I
Answer:
The sugars produced by photosynthesis can be stored, transported throughout the tree, and converted into energy which is used to power all cellular processes. Respiration occurs when glucose (sugar produced during photosynthesis) combines with oxygen to produce useable cellular energy.
Explanation:
I think this is correct lol.
Which statement best compares coal and ores?
Both are burned for energy.
Both take millions of years to form.
Both require oxygen to form.
Both are used to make coins.
Answer:
Option 2 both take millions of years to form
Explanation:
Both coal and ores take millions of years to form.
What are ores?Ore is a naturally occurring rock or silt that has precious minerals in it that may be extracted, processed, and sold for a profit. These minerals are usually metals. Mining is the process of removing ore from the soil. The valuable metals or minerals are then removed by treating or refining the ore, frequently through smelting.
The concentration of the desired ingredient in an ore is referred to as its grade. To decide if a rock has a high enough grade to be worth mining and is therefore regarded as an ore, the value of the metals or minerals it contains must be evaluated against the expense of extraction.
Typically, oxides, sulphides, silicates, or native metals like copper or gold are the minerals of interest. To separate the valuable components from the waste rock, ore must be treated. Numerous geological processes collectively known as ore genesis are responsible for the formation of ore deposits.
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A block of mass m1 = 19.5 kg slides along a horizontal surface (with friction, μk = 0.35) a distance d = 2.6 m before striking a second block of mass m2 = 8.25 kg. The first block has an initial velocity of v = 6.5 m/s.
(a) Assuming that block one stops after it collides with block two, what is block two's velocity after impact in m/s?
(b) How far does block two travel, d2 in meters, before coming to rest after the collision?
Answer:
19.5 m/s
87.8 m
Explanation:
The acceleration of block one is:
∑F = ma
-m₁gμ = m₁a
a = -gμ
a = -(9.8 m/s²) (0.22)
a = -2.16 m/s²
The velocity of block one just before the collision is:
v² = v₀² + 2aΔx
v² = (8.25 m/s)² + 2 (-2.16 m/s²) (2.3 m)
v = 7.63 m/s
Momentum is conserved, so the velocity of block two just after the collision is:
m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂
m₁u₁ = m₂v₂
(18.5 kg) (7.63 m/s) = (7.25 kg) v
v = 19.5 m/s
The acceleration of block two is also -2.16 m/s², so the distance is:
v² = v₀² + 2aΔx
(0 m/s)² = (19.5 m/s)² + 2 (-2.16 m/s²) Δx
Δx = 87.8 m
Explanation:
By using conservation of linear momentum and also by equating work done to kinetic energy, [tex]V_{2}[/tex] = 15.36 m/s and [tex]d_{2}[/tex] = 4.32 meters
Parameters given are :
[tex]m_{1}[/tex] = 19.5 kg
friction, μk = 0.35
distance d = 2.6 m
mass [tex]m_{2}[/tex] = 8.25 kg.
initial velocity of [tex]U_{1}[/tex] = 6.5 m/s.
a.) Since we assumed that the block one stops after it collides with block two, the final velocity for block one will be zero. That is, [tex]V_{1}[/tex] = 0 so its final momentum = 0
Let us also assume that block two was initially at rest. Therefore, it initial velocity and its momentum will be equal to zero.
The formula to use will be :
[tex]m_{1}U_{1} = m_{2}V_{2}[/tex]
Substitute all the parameters into the formula above
19.5 x 6.5 = 8.25[tex]V_{2}[/tex]
Make [tex]V_{2}[/tex] the subject of formula
[tex]V_{2}[/tex] = 126.75/8.25
[tex]V_{2}[/tex] = 15.36 m/s
b.) Let us first calculate the work done in by block one.
The K.E = [tex]1/2mU^{2}[/tex]
substitute its mass and velocity into the formula
K.E = 1/2 x 19.5 x [tex]6.5^{2}[/tex]
K.E = 411.94 Joule
The work done = Kinetic energy
But the resultant Force F = force f - friction
where Frictional force = 0.35 x 19.5 x 9.8
Frictional force = 66.89N
Work done will be the product of resultant Force F and the distance travelled
(F - 66.89) x 2.6 = 411.94
F - 66.89 = 411.94/2.6
F - 66.89 = 158.44
F = 225.3 N
The second block will experience the same force which is equal to 225.3N
Find the kinetic energy of the second block.
K.E = [tex]1/2mV^{2}[/tex]
K.E = 0.5 x 8.25 x 15.36^2
K.E = 973.2
Using The work done = Kinetic energy
225.3[tex]d_{2}[/tex] = 973.2
[tex]d_{2}[/tex] = 973.2/225.3
[tex]d_{2}[/tex] = 4.32 meters
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Animals conduct_______.
A. cellular respiration
B. photosynthesis
C. both cellular respiration and photosynthesis
a 6.25-gram bullet traveling at 365 ms strikes and enters a 4.50-kg crate. The crate slides 0.15 m along a wood floor until it comes to rest. What is the change in kinetic energy of the system after the collision
Answer:
the change in kinetic energy of the system is 0.577 J
Explanation:
Given;
mass of the bullet, m₁ = 6.25 g = 0.00625 kg
initial velocity of the bullet, u₁ = 365 m/s
mass of the crate, m₂ = 4.5 kg
initial velocity of the crate, u₂ = 0
distance moved by the system after collision, d = 0.15 m
Determine the final velocity of the system after collision;
m₁u₁ + m₂u₂ = v (m₁ + m₂)
0.00625 x 365 + 4.5 x 0 = v(0.00625 + 4.5)
2.2813 + 0 = v(4.5063)
2.2813 = v(4.5063)
v = 2.2813 / 4.5063
v = 0.506 m/s
The change in kinetic energy of the system after collision is calculated as;
ΔK.E = ¹/₂ (m₁ + m₂)v²
ΔK.E = ¹/₂ (4.506) x 0.506²
ΔK.E = 0.577 J
Therefore, the change in kinetic energy of the system is 0.577 J
The force of gravity on a person or object on the surface of a planet is called
A. gravity
ОВ.
B. free fall
OC
c. terminal velocity
D. weight
Answer:
D. Weight
Explanation:
Hope that helps:)
Magnus has reached the finals of a strength competition. In the first round, he has to pull a city bus as far as he can. One end of a rope is attached to the bus and the other is tied around Magnus's waist. If a force gauge placed halfway down the rope reads out a constant 2100 Newtons while Magnus pulls the bus a distance of 1.30 meters, how much work does the tension force do on Magnus
Answer:
Workdone = -2730 J
Explanation:
Formula for workdone is;
W = Force × Displacement
Now, according to Newton's 3rd law of motion, to every action, there is an equal and opposite reaction.
In the question given, we are told that a force gauge placed halfway down the rope reads out a constant 2100 Newtons while Magnus pulls the bus. This means that the force exerted by the rope on Magnus acts in an opposite direction to that which Magnus does to the rope.
Therefore, the force will be in the negative direction.
So;
Workdone = -2100 N × 1.3 m
Workdone = -2730 J
Q5. Use Superposition to V. in the circuit below? (5 points)
4 mA
12V
2 ΚΩ
2 mA
1 ΚΩ
2 ΚΩ
Answer:
4va
12va
2jk
1jk
2jk
difine precision and accuracy
Specify whether the boiling point, as determined in the miniscale boiling-point apparatus, is the temperature a.of the liquid at the timebubbles first emerge slowly from the liquid. b.at the vapor-liquid interface above the surface of the boiling liquid while a drop of liquid c.is suspended from the thermometer. d.of the liquid at the timebubbles emerge rapidly from the liquid. e.of the heating source at the timebubbles emerge rapidly from the liquid.
Answer:
a. of liquid at the time bubbles first emerge slowly from the liquid.
Explanation:
Boiling point of liquid happens due to heat energy. This is an exothermic reaction as heat is released in to the environment. The initial boiling vapors slowly move away from the liquid and as the temperature increases the vapors start moving quickly.
Any change in the cross section of the vocal tract shifts the individual formant frequencies, the direction of the shift depending on just where the change in area falls along the standing wave. Constriction of the vocal tract at a place where the standing wave of a formant exhibits minimum-amplitude pressure oscillations generally causes the formant to drop in frequency; expansion of the tract at those same places raises the frequency. Three other major tools for changing the shape of the tract in such a way that the frequency of a particular formant is shifted in a particular direction are the jaw, the body of the tongue and the tip of the tongue. Moving the various articulatory organs in different ways changes the frequencies of the two lowest formants over a considerable range [18].
One way to increase formant frequency is to ________ the vocal tract at a place where the standing wave of a formant frequency exhibits minimum-amplitude pressure oscillations.
a. Stretch
b. Vibrate
c. Contract
d. Expand
Answer:
The correct answer is option D.
Explanation:
It is stated in the question that constriction of the vocal tract at a place where the standing wave of a formant exhibits minimum-amplitude pressure oscillations generally causes the formant to drop in frequency so to increase formant frequency, the vocal should expand where the standing wave of a formant exhibits minimum-amplitude pressure oscillations. The answer is D.
I hope this helps.
how is work and energy inter-related?? (in simple words)
Answer:
The work and energy is inter- related because if we are energetic then only we are able to work.
People who are weak and not energetic cannot work continuously.
Explanation:
hope this helps you....
Galileo
o did not believe friction existed
o believed that friction stopped objects in motion
o believed that friction kept objects in motion
О
assumed that in a frictionless environment objects would never move
Answer:
object would move but it could be difficult to slow down or stop.
Which part of the water cycle is where vapor from plants leaves the plants as they breath?
condensation
Transpiration
evaporation
Answer:
I think it is transpiration
Answer:
transpiration is the right answer
A shuttle bus slows down with an average acceleration of -2.4 m/s2. How long does it
take the bus to slow from 9.0 m/s to rest?
Answer:
[tex]\boxed {\boxed {\sf 3.75 \ seconds }}[/tex]
Explanation:
Average acceleration is found by dividing the change in acceleration by the time.
[tex]a=\frac{ v_f-v_i}{t}[/tex]
The shuttle bus has an acceleration of -2.4 meters per square second. It slows from 9.0 meters per second to rest, or 0 meters per second. Therefore:
[tex]a= -2.4 \ m/s^2 \\v_f= 0 \ m/s \\v_i= 9 \ m/s[/tex]
Substitute the values into the formula.
[tex]-2.4 \ m/s^2=\frac{0 \ m/s - 9 \ m/s}{t }[/tex]
Solve the numerator.
[tex]-2.4 \ m/s^2 = \frac{-9 \ m/s}{t}[/tex]
We want to solve for t, the time. We have to isolate the variable. Let's cross multiply.
[tex]\frac{-2.4 \ m/s^2}{1} = \frac{-9 \ m/s}{t}[/tex]
[tex]-9 \ m/s *1= -2.4 \ m/s^2 *t[/tex]
[tex]-9 \ m/s=-2.4 m/s^2*t[/tex]
t is being multiplied by -2.4. The inverse of multiplication is division, so divide both sides by -2.4
[tex]\frac{-9 \ m/s }{-2.4 \ m/s^2} =\frac{ -2.4 \ m/s^2*t}{-2.4 \ m/s^2}[/tex]
[tex]\frac{-9 \ m/s }{-2.4 \ m/s^2} =t[/tex]
[tex]3.75 \ s=t[/tex]
It takes 3.75 seconds.
Two blocks connected by a string are pulled across a horizontal surface by a force applied to one of the blocks, as shown to the right. The mass of the left block m1 = 1.4 kg and the mass of the right block m2 = 4.9 kg. The angle between the applied force and the horizontal is θ = 54°. The coefficient of kinetic friction between the blocks and the surface is μ = 0.38. Each block has an acceleration of a = 3.6 m/s2 to the right.
Answer:
Explanation:The Mass Of The Left Block M1 = 1.3 Kg And The Mass Of The Right Block M2 = 3.1 Kg. The Angle Between The String And The Horizontal Is ... (10%) Problem 8: Two blocks connected by a string are pulled across a horizontal surface by a ... m m, 50% Part (a) Write an equation for the magnitude of the force exerted by the ...
1. Clara stops for 10 minutes to catch up with a friend.
Answer:
Clara has speed of 80m/min
Explanation:
Clara was jogging at 600 m in 5 minutes. She stopped suddenly which reduced her velocity and then she waited for 10 minutes so that her friends comes near her. She stopped to catch her friend. During this 10 minutes the velocity of Clara is zero. She started to walk again at a slower speed of 80m/min.
How far can a bus carrying small children, travel at a rate of 60 km per hour travel in 2 1/2 hours?
Explanation:
speed = 60km/hr.time = 2¹/2 hr = 5/2 hrdistance = speed × time = 60 ×5/2 = 150kmMARK ME AS BRAINLISTThe low-frequency speaker of a stereo set has a surface area of and produces 1W of acoustical power. What is the intensity at the speaker
Answer:
I = [tex]\frac{1}{4\pi \ r^2}[/tex]
we see the intensity decreases with the inverse of the distance squared
Explanation:
Intensity is defined as power per unit area,
I = P / A
in this case we have that the sound is emitted in a spherical form therefore the area is
A = 4 pi r2
therefore the intensity is
I = [tex]\frac{1}{4\pi \ r^2}[/tex]
as we see the intensity decreases with the inverse of the distance squared
Help with both questions I’ll mark brainliest
Answer:
gas, liquid, solid
sound cannot travel in space
Answer:
1. gas , liquid , gas
2.sound cannot travel in space