Answer:
a) the reflective surface has twice the energy transfer
b) A = 1.3 10²⁷ km²
c) the energy emitted by the sun is distributed in a sphere that depends on the square of the distance, and the gravitational force depends on the square of the distance
Explanation:
a) The pressure exerted on the candle is related to the variation of the momentum
P = [tex]\frac{1}{c} \ \frac{dp}{dt}[/tex]
in a case of absorption (inelastic shock) all the energy is absorbed therefore the pressure is
P = \frac{1}{c} \ \frac{dp}{dt}
in the case of reflection (elastic shock) an energy is absorbed by absorbing the light and then by action and reaction the same energy is absorbed in the reflected light
P = 2 \frac{1}{c} \ \frac{dp}{dt}
In conclusion, the reflective surface has twice the energy transfer.
b) pressure is defined with force per unit area
P = F / A
F = P A
this force must be greater than the gravitational force of attraction of the sun
Fg = G m Ms / r²
let's look for the case that the two forces are equal
F = Fg
P A_sail = G m Ms = r²
suppose a fully reflective sail
[tex]2 \frac{S}{c} \ A_{sail} = G \frac{m M_s}{r^2}[/tex]
The pointing vector is the power delivered per unit area
S = I = P / A
where A is the area of the sphere where the is distributed by the sun
A = 4π r²
we substitute
[tex]\frac{2P}{c} \ \frac{A_{sail}}{4 \pi r^2} = G \frac{m M_s}{r^2}[/tex]
[tex]\frac{1}{2 \pi \ c }[/tex] A_{sail} = G m M_s
A = G m M_s 2π c
let's calculate
A = 6.67 10⁻¹¹ 10000 2 10³⁰ 2π 3 10⁸
A = 1,257 10³³ m²
let's reduce to km²
A = 1.3 10³³ m² (1km / 10³ m) ²
A = 1.3 10²⁷ km²
c) The size of the candle is independent of the distance to the sun because the energy emitted by the sun is distributed in a sphere that depends on the square of the distance, and the gravitational force depends on the square of the distance, therefore the two dependencies are canceled.
3. A dog walks 12 meters to the east and then 16 meters back to the west.
For this motion, what is the distance moved?
What is the magnitude and direction of the displacemeni?
Answer:
[tex]distance = 16 + 12 \\ = 28 \: meters \\ \\ displacement = {}^{ + } 12 + {}^{ - } 16 \\ = - 4 \: meters \\ magnitude = > |s| = 4 \: meters[/tex]
You have a 6.00 V power supply, and
a 30.0 ohm and a 75.0 ohm resistor.
Find the current flowing out of the
battery if the resistors are connected
in parallel.
Answer: 0.28 A
Explanation:
Answer:
.28
Explanation:
Acellus
distance travelled/time taken gives?
Answer:
speed
Explanation:
Speed = distance travelled/time taken
Answer: Speed
Explanation:
Speed is defined as the rate of change of the position of an object in a direction. The speed of an object is calculated as the distance travelled divided by the time that is taken.
Speed is regarded as a scalar quantity since it has only direction but doesn't have magnitude. The answer to the above question is speed.
A sound has a higher pitch than a bell. Which quantity must also be higher in this sound than in the bell?
O amplitude
O frequency
O wavelength
O speed
Answer:
frequency
Explanation:
The frequency must also be higher in this sound than in the bell because for high pitch the frequency must be high.
What is the frequency?It is defined as the number of waves that crosses a fixed point in one second, known as frequency. The unit of frequency is per second.
We have:
A sound has a higher pitch than a bell.
As we know, the sound has a high pitch if the vibration frequency is high, and a low pitch if the vibration frequency is low.
Thus, the frequency must also be higher in this sound than in the bell because for high pitch the frequency must be high.
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POSSIBLE POINTS: 4
A sound wave traveling through a solid material has a frequency of 5 hertz. The wavelength of the sound wave is 2 meters. What is the speed of sound in
the material?
50 m/s
1,000 m/s
.
25 m/s
10 m/s
17
18 19 20 21 22 23 24 25 26
19 20 21 2
Ne
12631
MAY
20
0
étv
Answer:
v = fy
speed is equal to frequency × wavelength
5 × 2
[tex]10m.s^{ - 1} [/tex]
True or False: It would be easier to run on a planet with high gravity than one with less gravity.
Four passengers with combined mass 250 kg compress the springs of a car with worn out shock absorbers by 4.00cm when they enter it. Model the care and passengers as a single body on a single ideal spring. If the loaded has a period of vibration of 1.08 s, what is the period of vibration of the empty car?
Answer:
The time period of the empty car will be "1.00 s".
Explanation:
The given values in the question will be:
Mass,
m = 250 kg
Loaded car's time period will be:
T = 1.08 s
Shock absorbers compression,
x = 4 cm
or,
= 0.04 m
Now,
Weight of passengers will be:
⇒ [tex]F=mg[/tex]
[tex]=250\times 9.8[/tex]
[tex]=2450 \ N[/tex]
The spring constant of shock absorbers will be:
⇒ [tex]k=\frac{F}{x}[/tex]
[tex]=\frac{2450}{0.04}[/tex]
[tex]=61.250 \ N/m[/tex]
As we know,
Time period, [tex]T = 2 \pi\sqrt{\frac{M}{k} }[/tex]
On substituting the values, we get
[tex]1.08=2\pi \sqrt{\frac{M}{61250} }[/tex]
[tex]\frac{M}{61250}=0.02955[/tex]
[tex]M=0.02955\times 61250[/tex]
[tex]=1809.6 \ kg[/tex] (Total mass of car as well as its passengers)
Now,
The mass of the empty car will be:
⇒ [tex]m'=M-m[/tex]
[tex]=1809.6-250[/tex]
[tex]=1559.6 \ kg[/tex]
hence,
The time period of empty car will be:
⇒ [tex]T'=2\pi\sqrt{\frac{m'}{k} }[/tex]
[tex]=2\pi\sqrt{\frac{1559.6}{61250} }[/tex]
[tex]=2\pi \sqrt{0.0254}[/tex]
[tex]=1.003 \ s[/tex]
or,
[tex]=1.00 \ s[/tex]
what's is the best definition of AVERAGE SPEED?
Answer:
The average speed is the distance travelled divided by the time taken: Average speed=Distance travelledTime taken.
By how many times would the gravitational force between two objects decrease if the distance between the two objects was tripled?
Answer:
If the separation distance between any two objects is tripled (increased by a factor of 3), then the force of gravitational attraction is decreased by a factor of 9 (3 raised to the second power).
The plane has just taken off and reached a height of 200 m when one of its wheels falls off.
The wheel has a mass of 300 kg.
What speed does it hit the ground with?
(Ignore air resistance.)
Give your answer to the nearest 0.1 m/s
Use g = 9.8 m/s2 for the acceleration due to gravity.
A
6.3 m/s
Answer: 63 m/s
Explanation: If wheel drops vertically, you can use
conservation of energy : Ep = Ek. mgh = ½mv^2 and
solve v = √(2gh ) = √ (2·9.81 m/s²·200 m) = 62.6 m/s.
NOTE: wheel has also horizontal speed which was not mentioned here.
Pls help! Tysm!!! :D
Answer:
Slowing a bike by applying the brkaes is an xmaple of acceleration
Explanation:
A Thomson's gazelle can run at very high speeds, but its acceleration is relatively modest. A reasonable model for the sprint of a gazelle assumes an acceleration of 4.2m/s2 for 6.5s , after which the gazelle CONTINUES at a steady speed.
a. What is the gazelles top speed?
b. A human would win a very short race with a gazelle. The best time for a 30 m sprint for a human runner is 3.6 s. How much time would the gazelle take for a 30 m race?
Answer:
The correct answer will be:
(a) 27.3 m/s
(b) 3.8 s
Explanation:
According to the question:
Acceleration,
[tex]a= 4.2 \ m/s^2[/tex]
Time,
[tex]t = 6.5 \ s[/tex]
(a)
The gazelles top speed will be:
⇒ [tex]V_{max} = at[/tex]
[tex]=4.2\times 6.5[/tex]
[tex]=27.3 \ m/s[/tex]
or,
[tex]= 27 \ m/s[/tex]
(b)
As we know,
s = 30 m
Now,
⇒ [tex]s = \frac{1}{2} at^2[/tex]
or,
⇒ [tex]t=\sqrt{\frac{2s}{a} }[/tex]
On putting the given values, we get
[tex]=\sqrt{\frac{2\times 30}{4.2} }[/tex]
[tex]=\sqrt{\frac{60}{4.2} }[/tex]
[tex]=3.78 \ s[/tex]
or,
[tex]=3.8 \ s[/tex]
A block of mass 3m is placed on a frictionless horizontal surface, and a second block of mass m is placed on top of the first block. The surfaces of the blocks are rough. A constant force of magnitude F is applied to the first block as shown in the figure. (a) Construct free-body diagrams for each block. (b) Identify the horizontal force that causes the block of mass m to accelerate. (c) Assume that the upper block does not slip on the lower block, and find the acceleration of each block in terms of m and F.
By Newton's second law, assuming F is horizontal,
• the net horizontal force on the larger block is
F - µmg = 3mA
where µmg is the magnitude of friction felt by the larger block due to rubbing with the smaller one, µ is the coefficient of static friction between the two blocks, and A is the block's acceleration;
• the net vertical force on the larger block is
4mg - 3mg - mg = 0
where 4mg is the mag. of the normal force of the surface pushing up on the combined mass of the two blocks, 3mg is the weight of the larger block, and mg is the weight of the smaller block;
• the net horizontal force on the smaller block is
µmg = ma
where µmg is again the friction between the two blocks, but notice that this points in the same direction as F. It is the only force acting on the smaller block in the horizontal direction, so (b) static friction is causing the smaller block to accelerate;
• the net vertical force on the smaller block is
mg - mg = 0
where mg is the magnitude of both the normal force of the larger block pushing up on the smaller one, and the weight of the smaller block.
(You should be able to draw your own FBD's based on the forces mentioned above.)
(c) Solve the equations above for A and a :
A = (F - µmg) / (3m)
a = µg
A man rides a bike along a straight road at a constant speed for 5 minmin, then has a flat tire. He stops for 5 minmin to repair the flat, but then realizes he cannot fix it. He continues his journey by walking the rest of the way at a constant speed, which takes him another 10 min.
Required:
Use the particle model to draw a motion diagram of the man for the entire motion described here. Number the dots in order, starting with zero.
what are the advantages of having a roof with a lower thermal conductivity?
Which of the following two is correct
Less energy is needed to heat the house
The roof is a better insulator
The roof is less likely to leak
The rate of energy transfer by conduction is greater
Weather will have a greater effect on the temperature of the house
Answer:
less energy is needed to heat the house
the roof is a better insulator
The correct advantage of having a roof with a lower thermal conductivity is Less energy is needed to heat the house. The correct answer is option 1.
A roof with lower thermal conductivity acts as a better insulator, reducing heat transfer between the interior and exterior of the house. This means that during colder months, less heat escapes through the roof, requiring less energy to maintain a comfortable temperature indoors. Additionally, a roof with lower thermal conductivity will help regulate indoor temperatures more effectively, making it a better insulator against external weather conditions. It does not directly affect the likelihood of roof leaks or increase the rate of energy transfer by conduction. Option 1 is correct.
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--The complete Question is, What are the advantages of having a roof with a lower thermal conductivity?
Which of the following two is correct
1. Less energy is needed to heat the house
2. The roof is a better insulator
3. The roof is less likely to leak
4. The rate of energy transfer by conduction is greater
5. Weather will have a greater effect on the temperature of the house. --
A waterfall is an example of what energy conversion?
Answer:
most common energy transformations is the transformation between potential energy and kinetic energy. In waterfalls such as Niagara Falls, potential energy is transformed to kinetic energy. The water at the top of the falls has gravitational potential energy. As the water plunges, its velocity increases.
Explanation:
Hope this helps you
( I got this from transformation and conservation article)
What is the period of a wave that completes 3 waves in 2 seconds?
P = 3÷2
= 1.5
Explanation:
hope it helps
What materials are difficult to charge because electrons easily flow through them?
Answer:
Conductors
Explanation:
If you build a circuit with 3 D batteries, what is the voltage of the circuit?
A) 3 volts
B) 4.5 volts
C) 3 Amps
D) 4.5 Ohms
Answer:
a
Explanation:
Answer:
d
Explanation:
Which ones are correct??
Answer:
blanket:thermal conductivity
as it conduct heat.
aquarium glass:transparency
as light can be transfered from one side to
another.
(1) Viewers of Star Trek hear of an antimatter drive on the Starship Enterprise. One possibility for such a futuristic energy source is to store antimatter charged particles in a vacuum chamber, circulating in a magnetic field, and then extract them as needed. Antimatter annihilates with normal matter, producing pure energy. What strength magnetic field is needed to hold antiprotons, moving at 5.0 x 10^7 m/s in a circular path 2.00 m in radius? Antiprotons have the same mass as protons but the opposite (negative) charge.
(2) Is this field strength obtainable with today’s technology or is it a futuristic possibility?
Solution :
The relationship between the strength of magnetic field and the radiusof a charged particle's path is obtained through Newton's second law, which is given by :
F = ma
F = qvB and [tex]$a=\frac{v^2}{r}$[/tex]
Substituting these values in the second law of Newton,
[tex]$qvB=\frac{mv^2}{r}$[/tex]
Now solving for B, we get:
[tex]$B = \frac{mv}{rq}$[/tex]
[tex]$=\frac{(1.67 \times 10^{-27})(5 \times 10^{7})}{2\times 1.6 \times 10^{-19}}$[/tex]
= 0.261 T
The field strength can be obtained by using the technology of today.
An initially uncharged sphere is on an insulated stand and isolated in a chamber. The charge on the sphere is monitored as a beam of monochromatic light shines on the sphere. Initially nothing happens. The wavelength of the light is slowly decreased. When the wavelength reaches a certain value, a positive charge is suddenly measured on the sphere. The wavelength is then held constant, and the charge continues to increase at a constant rate. The intensity of the beam is then increased without the wavelength being changed, and the rate of increase of the charge becomes greater.
Required:
a. In a coherent paragraph-length response, describe the cause of the charge on the sphere and the changes in the observations about the charge, in terms of physics principles.
b. An electron in the chamber is moving with speed 2×10^5m/s when it collides with a positron (a particle identical to an electron except for the sign of its charge) moving with the same speed in the opposite direction. The particles annihilate each other. How much energy is released due to the annihilation?
c. In another experiment, a beam of electrons with uniform wavelength λe is incident on a slit, where the width of the slit is much larger than λe. A detector is placed near the slit, but no diffraction pattern is observed. What change should be made that would result in a diffraction pattern? Indicate why this change is the one needed.
Answer:
a) E = K + Φ, b) ΔE = 1.64 10⁻¹³ J., c) λ = a
Explanation:
a) In this case it is an example of the photoelectric effect that was correctly described by Einstein assuming that the light ray is composed of a series of particles called photons, each one with an energy given by the Planck equation
E = h f
c = λ f
substituting
E = h c /λ
We can see from this equation that as the wavelength of the ray decreases the energy of each photon increases, the moment arrives that the energy is sufficient to remove an electron from the sphere, thus leaving an unbalanced positive charge, this description explains why the positive charge appears on the sphere; the minimum wavelength to remove an electron is
E = K + Φ
if K = 0
E =Φ
where fi is the work function of the material.
When the intensity of the ray increases according to Eintein's description, the number of photons increases, so if the number of photons increases, the number of shocks and the number of electrons expelled increases, therefore the unbalanced positive charge also increases.
b) the energy released in collision is the sum of the energy of each particle
for the electron
E = K + m c² = (pc) ² + (m c²) ²
where the moment is
p = γ m u
γ = [tex]\sqrt{1- (\frac{u}{c})^2 }[/tex]
γ = [tex]\sqrt {1- ( \frac{2 \ 10^5}{3 \ 10^8 })^2 } = \sqrt{1- (6.67 \ 10 ^{-4)^2 }[/tex]
γ ≅ 1
in this case since the speed of the particles is much less than the speed of light,
E = (m u) ² + (m c²) ²
E = m² (u² + c²)
E = 9.1 10⁻³¹ [(2 10⁵) ² + (3 10⁸) ²
E = 9.1 10⁻³¹ 9 10¹⁶
E = 8.2 10⁻¹⁴ J
the positron has an energy of equal magnitude, so when the two particles annihilate the energy change is
ΔE = 2E
ΔE = 2 (8.2 10⁻¹⁴)
ΔE = 1.64 10⁻¹³ J.
c) the expression that describes the diffraction process is
a sin θ = m λ
sin θ = m λ/ a
where a is the width of the slit and m in diffraction order
The greatest value that the sine function can have is 1
1 = m λ / a
λ = a / m
therefore we can see that to see the diffraction phenomenon the width of the slit must be greater than or equal to the wavelength
Violet light (410 nm) and red light
(685 nm) pass through a diffraction
grating with d = 3.33 x 10-6 m. What is
the angular separation between them
for m = 2?
Answer:10.03
Explanation:acellus
Tritium and helium-3 have the same number of nucleons, but tritium has one proton and two neutrons whereas helium-3 has two protons and one neutron. Without doing a calculation, decide which nucleus has a greater binding energy. Explain. (Select all that apply.)
a. This happens in part because the tritium nucleus has greater Coulombic repulsion.
b. This happens in part because the helium-3 nucleus has greater Coulombic repulsion between nucleons.
c. This happens in part because the tritium nucleus has an extra neutron enhancing the nuclear forces.
d. Helium-3 is more stable.
e. This happens in part because the helium-3 nucleus has fewer neutrons.
f. Tritium is more stable.
Answer:
Tritium is more stable.
This happens in part because the tritium nucleus has an extra neutron enhancing the nuclear forces.
Explanation:
The binding energy is the energy that holds nucleons together in the nucleus. It depends on the number of nucleons present in the nucleus. The greater the number of nucleons, the greater the binding energy.
Also, the more the number of neutrons in a nucleus, the greater the nuclear forces. Helium-3 has only one neutron while tritium has two neutrons. The extra neutron in tritium enhances the nuclear forces hence tritium has a greater binding energy than Helium-3
Tritium is more stable.this happens in part because the tritium nucleus has an extra neutron enhancing the nuclear forces.
What is binding energy?
The binding energy is the energy that holds nucleons together in the nucleus. It depends on the number of nucleons present in the nucleus.
The greater the number of nucleons, the greater the binding energy.Also, the more the number of neutrons in a nucleus, the greater the nuclear forces.
Helium-3 has only one neutron while tritium has two neutrons. The extra neutron in tritium enhances the nuclear forces hence tritium has greater binding energy than Helium-3
Thus tritium is more stable.this happens in part because the tritium nucleus has an extra neutron enhancing the nuclear forces.
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A thin film of acetone (n=1.25) lies on the surface of a thick piece of water (n=1.30). White light shines down from air onto the thin layer of acetone. Destructive interference occurs for m=3 for a wavelength in air of 600 nm. What is the thickness of the thin film?
Answer:
Explanation:
The wave of light is being reflected two times while going from lower to higher refractive index mediums
So there will be phase reversal two times .
Condition of destructive index
2 μ t = ( 2m+1) λ / 2
Substituting the values
2 x 1.25 x t = ( 2 x 3 + 1 ) x 600nm / 2
2.5 t = 2100 nm
t = 840 nm .
Explain the difference between the speed of an Electromagnetic wave and its frequency?
Answer:
Electromagnetic waves differ in their wavelengths and frequencies. The higher the frequency of an electromagnetic wave, the greater its energy. The speed of an electromagnetic wave is the product of its wavelength and frequency, so a wave with a shorter wavelength has a higher frequency, and vice versa.
Explanation:
What is hydrometer? Describe its use and any one type of hydrometer.
Answer:
An instrument for measuring the density of liquids.
Explanation:
A hydrometer is an instrument used to determine specific gravity. It operates based on the Archimedes principle that a solid body displaces its own weight within a liquid in which it floats. Hydrometers can be divided into two general classes: liquids heavier than water and liquids lighter than water.
Thermohydrometers is one type of hydrometer.
A person pulls a box across the floor with a rope. The rope makes an angle of 40 degrees tot he horizontal, and a total of 125 newtons of force is applied. How much work is done if the box is pulled for 25 meters?
Answer:
The angle formed of the rope with the surface = 40°
Force applied = 125Newtons
The displacement covered by the box =25metres
W= FDcos theta
[125×40×cos(40°) ] Joules
= [ (3125×0.76604444311)]Joules
= 2393.88888472 joules(ans)
Hope it helps
It takes 24 hours for _______?
a.Earth to circle the sun one time
b.earth to rotate on its axis one time
c. The sun to circle earth one time
d.the sun to rotate on its axis one time
Answer:
C
Explanation:
Earth rotates once in about 24 hours with respect to the Sun, but once every 23 hours, 56 minutes, and 4 seconds with respect to other, distant, stars. Earth's rotation is slowing slightly with time; thus, a day was shorter in the past. This is due to the tidal effects the Moon has on Earth's rotation.
Answer: the answer is b.
ps: the other answer is wrong, the earth rotates around the sun, and the sun doesn't rotate around the earth.
Explanation:
What did Europeans, africans and Americans trade as a result for the Colombian exchange
A. Railroad engineering ideas
B. Computer technology
C. Film production techniques
D. Agricultural knowledge
Also under the subject I meant to put social studies not physics.
Answer: Railroad engineering ideas