Answer:
60 ft
Explanation:
The tree man and their shadow system forms two similar right angle triangles.
the figure is in the attachment.
let ∠BAC= θ
Therefore, in triangle ABC
tanθ = BC/AC= 35/75= 7/15
now in ΔAEF also
tanθ = EF/AE = 7/75-x= 7/15
solving we get x=60 ft
Now AC and FA are the shadows of the tree and the man respectively.
now FA =75-x=75-60= 15 ft
Therefore, the man must stand at a distance of 60 ft from the tree can you stand and still be completely in the shadow of the tree
A person 7 feet tall can stand 60 feet away from a 35-foot tree casting a 75-foot shadow to be completely in the shadow of the tree.
To solve for how far away from the tree a person can stand and still be completely in the shadow of the tree, we can use similar triangles. Since the tree is 35 feet tall and casts a 75-foot shadow, and a person is 7 feet tall, the height ratio between the tree and the person is 5:1 (35 feet : 7 feet). Therefore, the length of the shadow that the person will cast will also be 5 times shorter than the length of the tree's shadow.
We calculate the length of the person's shadow as follows:
Length of person's shadow = Length of tree's shadow / Height ratio
Length of person's shadow = 75 feet / 5
Length of person's shadow = 15 feet
The total distance from the tree at which the person can stand and still be completely in the shadow is the length of the tree's shadow minus the length of the person's shadow.
Total distance from the tree = Length of tree's shadow - Length of person's shadow
Total distance from the tree = 75 feet - 15 feet
Total distance from the tree = 60 feet
How does a coal-fired power plant use the energy in coal to produce electricity?
Coal-fired power plants produce electricity by burning coal to boil water into steam, which drives a turbine connected to a generator. The efficiency of energy conversion is low, with significant heat loss to the environment and a large CO2 emission as one of the main environmental impacts.
Explanation:A coal-fired power plant converts the energy stored in coal into electricity through a multi-step process. First, coal is mined and processed to be suitable for burning. When coal is combusted in the plant, it heats water to turn it into steam. The steam at high pressure then drives a turbine, which is connected to a generator. As the turbine blades turn, they rotate the generator, which converts the kinetic energy into electricity. This process involves significant heat transfer to the surroundings, which is an inherent part of energy production from combustion.
During the energy conversion process, the efficiency of coal power stations is quite low, with only about 42% of the energy being used for electricity generation and the rest being lost as heat transfer to the environment. The chemical reaction during the combustion of coal is C + O2 → CO2, and a significant amount of CO2 is emitted into the atmosphere. This contributes to the warming of our planet, and coal power plants are known for being the least efficient and most CO2-emitting fossil fuel energy sources.
Friction a. is slow but steady movement along a fault. b. happens when rock is weak and can slip smoothly, without creating shock waves. c. is the process by which faults release energy. d. is the force that resists sliding along a surface
Answer:
option D
Explanation:
The correct answer is option D
The friction force is the force that holds back the surface from sliding. It acts in the opposite direction of the motion of the body.
It can be explained with an example,
when you throw a ball on the ground it stops automatically this is because of friction which is acting opposite to the ball.
Friction also has benefits like due to friction we can walk, run, etc.
So, from the given option
The force that resists sliding is friction force.
A system has three macrostates. Macrostates 1 and 3 are least likely and have one basic state each. Macrostate 2 is the equilibrium state and is four times more likely to occur than either of the other two macrostates.
Part A
What is the probability that the equilibrium state 2 occurs?
Express your answer using three significant digits.
p2=
Part B
What is the probability that macrostate 1 occurs?
Express your answer using three significant digits.
p1=
Part C
What is the probability that macrostate 3 occurs?
Express your answer using three significant digits.
p3=
Part D
What is the sum of the probabilities for all macrostates?
Express your answer using three significant digits.
p=
Answer:
[tex]p2=0.667\\p1=0.167\\p3=0.167\\p=1[/tex]
Explanation:
Let's start writing the sample space for this exercise :
Let be ''M'' an abbreviation for Macrostate
Ω = { M1 , M2 , M3 }
Let be P(M1) the probability of Macrostate 1.
Reading the exercise, we know that ⇒
[tex]P(M1)=P(M3)[/tex]
Let's note this probability as ''p''.
[tex]P(M1)=P(M3)=p[/tex]
Macrostate 2 is four times more likely to occur than either of the other two macrostates ⇒
[tex]P(M2)=4p[/tex]
The sum of all probabilities must be equal to 1 for this sample space.Therefore,
[tex]p+p+4p=1[/tex]
[tex]6p=1[/tex]
[tex]p=\frac{1}{6}[/tex]
Finally :
[tex]P(M1)=\frac{1}{6}[/tex]
[tex]P(M2)=\frac{4}{6}[/tex]
[tex]P(M3)=\frac{1}{6}[/tex]
For Part A :
[tex]p2=\frac{4}{6}=0.667[/tex]
For Part B and C :
[tex]p1=p3=0.167[/tex]
For Part D :
The sum of the probabilities for all macrostates is equal to 1 :
[tex]p=p1+p2+p3=\frac{1}{6}+\frac{4}{6}+\frac{1}{6}=\frac{6}{6}=1[/tex]
Final answer:
The probability that equilibrium state 2 occurs is approximately 0.667. The probability that macro state 1 or macro state 3 occurs is each approximately 0.167. The sum of the probabilities for all macro states is exactly 1, as expected for a complete set of possible outcomes.
Explanation:
To find the probability of each macro state, we first recognize that the probabilities must sum to 1 for all macro states. Given that the equilibrium state, Macro state 2, is four times more likely than either of the other two Macro states 1 and 3, we can assign a probability 'p' to Macro states 1 and 3 and '4p' to Macro state 2.
Let's assume:
Probability of Macro state 1, p1 = p
Probability of Macro state 2, p2 = 4p
Probability of Macro state 3, p3 = p
Since the total probability must equal 1, we write the equation:
p1 + p2 + p3 = 1
Substituting the assumed probabilities gives:
p + 4p + p = 1
6p = 1
Therefore, p = 1/6
Now, we can calculate each probability:
p1 = 1/6 ≈ 0.167
p2 = 4/6 ≈ 0.667
p3 = 1/6 ≈ 0.167
The sum of all probabilities, p, is as expected:
p = p1 + p2 + p3 = 0.167 + 0.667 + 0.167 = 1
Wearing a seat belt protects you from possible harm by a certain force. Which force?
Explain the difference between weight and mass.
What force causes objects to move in a circular path?
Answer:
push
Explanation:
it pushes you back when you lean forward really fast
The difference between mass and weight is that mass is the amount of matter in a material, while weight is a measure of how the force of gravity acts upon that mass. Mass is the measure of the amount of matter in a body. ... Weight usually is denoted by W. Weight is mass multiplied by the acceleration of gravity (g).
GRAVITY
THE UNBALANCED FORCE THAT CAUSES OBJECTS TO MOVE IN A CIRCULAR PATH IS CALLED A CENTRIPETAL FORCE. GRAVITY PROVIDES THE CENTRIPETAL FORCE THAT KEEPS OBJECTS IN ORBIT. THE WORD CENTRIPETAL MEANS "TOWARD THE CENTER."
A museum curator moves artifacts into place on various different display surfaces. If the curator moves a 145 kg aluminum sculpture across a horizontal steel platform what is fs, fmax, and fk
Answer:
Static friction is, [tex]0\ N\leq f_s\leq 866.81\ N[/tex]
Maximum static friction is, [tex]f_{max}= 866.81\ N[/tex]
Kinetic friction is, [tex]f_k=667.87\ N[/tex]
Explanation:
The value of coefficient of static friction between Aluminium and Steel is [tex]\mu_s=0.61[/tex] and the value of coefficient of kinetic friction is [tex]\mu_k=0.47[/tex]
Given:
Mass of the sculpture is, [tex]m=145\ kg[/tex].
As the sculpture is moved along the horizontal direction only, there will no net force acting along the vertical direction. Therefore,
Normal force by the steel platform will be equal to the weight of the aluminium sculpture. That is,
[tex]N=mg[/tex]
Now, the static friction is given as the product of normal force and coefficient of static friction. The static friction varies from a value of 0 to limiting friction.
The limiting friction is the maximum static friction that acts on a body to resist the motion.
The value of the limiting friction or the maximum static friction is given as:
[tex]f_{max}=\mu_sN=\mu_smg=0.61\times 145\times 9.8=866.81\ N[/tex]
Thus, static friction is given as:
[tex]0\leq f_s\leq f_{max}\\0\leq f_s\leq \mu_smg\\0\ N\leq f_s\leq 866.81\ N[/tex]
Now, kinetic friction is the frictional force acting on a body when the body is moving under the action of forces. Thus kinetic friction is the product of normal force and coefficient of kinetic friction. Kinetic friction is a constant opposing force.
Thus, kinetic friction is given as:
[tex]f_k=\mu_kN\\f_k=\mu_kmg\\f_k=0.47\times 145\times 9.8=667.87\ N[/tex]
An airplane propeller is 2.68 m in length (from tip to tip) and has a mass of 107 kg. When the airplane's engine is first started, it applies a constant torque of 1930 Nm to the propeller, which starts from rest.
a. What is the angular acceleration of the propeller? Treat the propeller as a slender rod.
b. What is the propeller's angular speed after making 5.00 rev?
c. How much work is done by the engine during the first 5.00 rev?
d. What is the average power output of the engine during the first 5.00 rev?
e. What is the instantaneous power output of the motor at the instant that the propeller has turned through 5.00 rev?
Answer:
a)30.14 rad/s2
b)43.5 rad/s
c)60633 J
d)42 kW
e)84 kW
Explanation:
If we treat the propeller is a slender rod, then its moments of inertia is
[tex] I =\frac{mL^2}{12} = \frac{107*2.68^2}{12} = 64.04 kgm^2[/tex]
a. The angular acceleration is Torque divided by moments of inertia:
[tex]\alpha = \frac{T}{I} = \frac{1930}{64.04} = 30.14 rad/s^2[/tex]
b. 5 revolution would be equals to [tex]10\pi[/tex] rad, or 31.4 rad. Since the engine just got started
[tex]\omega^2 = 2\alpha\theta = 2*30.14*31.4 = 1893.5[/tex]
[tex]\omega = \sqrt{1893.5} = 43.5 rad/s[/tex]
c. Work done during the first 5 revolution would be torque times angular displacement:
[tex]W = T*\theta = 1930 * 31.4 = 60633 J[/tex]
d. The time it takes to spin the first 5 revolutions is
[tex]t = \frac{\omega}{\alpha} = \frac{43.5}{30.14} = 1.44 s[/tex]
The average power output is work per unit time
[tex]P = \frac{W}{t} = \frac{60633}{1.44} = 41991 W[/tex] or 42 kW
e.The instantaneous power at the instant of 5 rev would be Torque times angular speed at that time:
[tex]P_i = T*\omega = 1930*43.5=83983 W[/tex] or 84 kW
A pressure vessel at rest at the origin of an xy coordinate system explodes into three pieces that remain in the xy plane. Just after the explosion, one piece, of mass m, moves with velocity (−30 �/�)� and a second piece, also of mass m, moves with velocity (−30 �/�)�. The third piece has mass 3m. Just after the explosion, what is the velocity of the third piece? Use unit vector notation.
Answer:
v₃ = (10) i + (10) j
v₃ = 10√2
Explanation:
Given info
Before the explosion
ux = 0
uy = 0
After the explosion
v₁x = -30
v₁y = 0
v₂x = 0
v₂y = -30
We can use the Principle of Conservation of Momentum as follows
pi = pf
where
pix = M*ux = M*0 = 0
piy = M*uy = M*0 = 0
pfx = p₁x + p₂x + p₃x = (m*v₁x + m*v₂x + 3m*v₃x) = m*(-30) + m*(0) + 3m*v₃x
⇒ pfx = -30m + 3m*v₃x
if
pix = pfx ⇒ 0 = -30m + 3m*v₃x ⇒ v₃x = 10
pfy = p₁y + p₂y + p₃y = (m*v₁y + m*v₂y + 3m*v₃y) = m*(0) + m*(-30) + 3m*v₃y
⇒ pfy = -30m + 3m*v₃y
if
piy = pfy ⇒ 0 = -30m + 3m*v₃y ⇒ v₃y = 10
then we have
v₃ = (10) i + (10) j
and its module can be obtained as follows
v₃ = √(v₃x² + v₃y²) = √(10² + 10²) = 10√2
IE is the energy required to remove an electron from an atom. As atomic radius increases, the valence electrons get farther from the nucleus. How do you think an atom’s size will affect its ability to hold on to its valence electrons? Why?
Answer:
The bigger the atom the lesser the ability of the atom to hold on to its valence electrons.
Explanation:
Atomic radius can be looked at as the distance between the nucleus and the outermost energy level. As an atom gets bigger, the outer shell gets further and further from the positive nucleus. this means that electrons that are in the outer energy level become less held (attracted) by the nucleus because of distance and shielding of the attractive forces by the electrons in the lower energy levels. This means that as an atom becomes bigger, its ability to hold on to its outer electrons lessens.
As an atom gets larger, it is unable to hold its valence electrons due to decreased electrostatic attraction between the nucleus and the valence electron.
An atom is composed of a nucleus that houses positive charges and an electron which is negatively charged and are found in orbits. Electrostatic attraction between the positively charged nucleus and electrons in orbits keep the atom together.
However, as an atom gets larger, the valence electrons are farther away from the nucleus. As the distance between the nucleus and the outermost electrons increases, the electrostatic interaction between electron and the nucleus is decreased according to Coulomb's law. Repulsion (screening) between inner and valence electrons further keep the valence electrons away from the attractive forces of the nucleus.
Therefore, as an atom gets larger, it is unable to hold its valence electrons due to decreased electrostatic attraction between the nucleus and the valence electrons.
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How much work is done by a force vector F = (4x N)i hat +(5 N)j, with x in meters, that moves a particle from a position vector r i = (5 m)i hat +(6 m)j, to a position vector r f = -(2 m)i hat -(5 m)j?
Answer:
-83
Explanation:
How do i calculate acceleration? pls help! thanks :)
As I drive down South Hill toward downtown Spokane, my car goes from a velocity of 25 mph north to a velocity of 35 miles an hour north in 5 minutes. What is my acceleration during this time?
5 mph / minute
2 mph / min squared
10 mph
The acceleration is 2 mph/min
Explanation:
The acceleration of an object is the rate of change of velocity. It is defined as follows:
[tex]a=\frac{v-u}{t}[/tex]
where
v is the final velocity
u is the initial velocity
t is the time taken for the velocity to change from u to v
For the car in this problem, we have (taking North as positive direction):
u = 25 mph
v = 35 mph
t = 5 min
Substituting into the equation, we find the acceleration:
[tex]a=\frac{35 mph-25mph}{5min}=2 mph/min[/tex]
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A person is standing on a spring bathroom scale on the floor of an elevator which is moving up and slowing down at the rate of 3 m/s 2 . The acceleration of gravity is 9.8 m/s 2 . If the person’s mass is 93.3 kg, what does the scale read? Answer in units of n.
Answer:
[tex]F_N=1194.24\ N[/tex]
Explanation:
Given that,
The elevator is moving up and slowing down at the rate of, [tex]a=3\ m/s^2[/tex]
The acceleration due to gravity, [tex]g=9.8\ m/s^2[/tex]
Mass of the person, m = 93.3 kg
To find,
The reading of the scale.
Solution,
As the elevator is moving down with some acceleration. The net force acting on it is given by :
[tex]F_N=ma+mg[/tex]
[tex]F_N=m(a+g)[/tex]
[tex]F_N=93.3(3+9.8)[/tex]
[tex]F_N=1194.24\ N[/tex]
So, the scale will read 1194.24 N.
When 0.1375 g of solid magnesium is burned in a constant-volume bomb calorimeter, the temperature increases by 1.126°C. The heat capacity of the bomb calorimeter, determined in a separate experiment, is 3024 J/°C. Calculate the heat given off by the burning magnesium in kJ/mol.
Answer:
-24.76 kJ/mol
Explanation:
given,
mass of solid magnesium burned = 0.1375 g
the temperature increases by(ΔT) 1.126°C
heat capacity of of bomb calorimeter (C_{cal})= 3024 J/°C
heat absorbed by the calorimeter
[tex]q_{cal} = C_{cal}\DeltaT[/tex]
[tex]q_{cal} = 3024 \times 1.126[/tex]
[tex]q_{cal} =3405.24\ J[/tex]
[tex]q_{cal} =3.405\ kJ[/tex]
heat released by the reaction
[tex]q_{rxn} = -q_{cal}[/tex]
[tex]q_{rxn} = -3.405\ kJ[/tex]
energy density will be equal to heat released by the reaction divided by the mass of magnesium
Energy density = [tex]\dfrac{-3.405}{0.1375}[/tex]
Energy density = -24.76 kJ/mol
heat given off by burning magnesium is equal to -24.76 kJ/mol
An Object is moving due south at 16 m/s, when a force accelerates it at 4m/s in a southerly direction. How long will it take for the object to reach a velocity of 48 m/s south. Please help me out.
Answer:
Time taken to accelerate to 48 m/s = 8 seconds
Explanation:
Initially the object is moving south at = [tex]16 m/s[/tex]
So, initial velocity of the object = [tex]16 m/s[/tex]
Acceleration caused by the force = 4 [tex]m/s^2[/tex]
Final velocity towards south = [tex]48 m/s[/tex]
Using equation of motions:
[tex]v_f=v_i+at[/tex]
where
[tex]v_f\rightarrow[/tex] final velocity
[tex]v_i\rightarrow[/tex] initial velocity
[tex]a\rightarrow[/tex] acceleration
[tex]t\rightarrow[/tex] time
Plugging in values.
[tex]48=16+(4)t[/tex]
[tex]48=16+4t[/tex]
Subtracting both sides by 16
[tex]48-16=16+4t-16[/tex]
[tex]32=4t[/tex]
Dividing both side by 4.
[tex]\frac{32}{4}=\frac{4t}{4}[/tex]
[tex]8=t[/tex]
∴ [tex]t=8[/tex]
Time taken to accelerate to 48 m/s = 8 seconds
A person exerts a horizontal force of 190 n in the test apparatus shown in the figure. Find the horizontal force that his flexor muscle exerts on his forearm.
Answer:
Check explanation.
Explanation:
From the question, we know that The person exerted 190N, force on the flexor is unknown. Since, we don't have access to our diagram, we have to make one or two assumption; (1) that ba= 0.3 m, ac= 0.05.
Therefore, the horizontal force that his flexor muscle exerts on his forearm,F(flexor) = (190N) × (0.3m) / 0.05m.
The horizontal force that his flexor muscle exerts on his forearm,F(flexor) = 57 Nm/ 0.05 m.
The horizontal force that his flexor muscle exerts on his forearm,F(flexor) = 1140N.
Using principles of physics, specifically equilibrium, we know the force exerted by muscles can be greater than the load they support, especially when the load is distant from the joint. In the case of a 190 N horizontal force, the exact force of the flexor muscle can't be calculated without more information, but it's likely larger than 190 N.
Explanation:To answer the student's question, we must refer to concepts in physics, specifically the principle of equilibrium and the analysis of free-body diagrams. Given that the student is trying to find the force that a person's flexor muscle exerts horizontally when the person exerts a horizontal force of 190 N.
As mentioned in the provided information, forces and tensions in muscles and joints can be quite substantial. In this scenario, the flexor muscle in the forearm is acting against the applied force to maintain balance or equilibrium. This can be seen in the free-body diagram where forces are broken down into their x- and y-components.
It's important to note that the force exerted by muscles can be far greater than the load they support, especially when the load is a considerable distance from the joint, as stated in the provided text snippet. This may be relevant when analyzing the muscle force in this scenario.
Unfortunately, without more specific details about the angles involved and the exact configuration of the arm and forearm in the test apparatus, we can't calculate the exact force exerted by the flexor muscle. However, we can say that it's likely to be substantially larger than the 190 N applied force, considering the principles discussed above.
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A manufacturer claims to have built a home stereo speaker that is 4 feet tall but uses an average of only 30 watts of power. A sample of 40 speakers from the manufacturer found that they used an average of 32 watts of power. The appropriate hypotheses to test the manufacturer’s claim are?
Answer:
Original claim is H_o: M = 30
Alternate claim is H_a: M > 30.
Explanation:
Given data:
4 ft tall speaker consume 30 watt power
a group of 40 speaker consume average power of 32 watt
calculation:
A home installed 4 ft tall speaker that use 30 watt Power
40 speakers used 32 watt Power
Original claim is H_o: M = 30
Alternate claim is H_a: M > 30.
An object is solid throughout. When the object is completely submerged in ethyl alcohol, its apparent weight is 16.5 N. When completely submerged in water, its apparent weight is 13.3 N. What is the volume of the object?
Answer:
V = 1.7 x 10^{-3} m^{3}
Explanation:
apparent weight in ethyl alcohol = 16.5 N
apparent weight in water = 13.3 N
apparent weight = mg - ρgV
where
m = mass
g = acceleration due to gravity = 9.8 m/s^{2}
ρ = density
V = volume
for ethyl alcohol 16.5 = mg - ρ₁gV .....equation 1for water 13.3 = mg - ρ₂gV .......equation 2we can solve the two equations above as simultaneous equations by subtracting equation 2 from equation 1
we have
16.5 - 13.3 = (mg - mg) - ρ₁gV - (-ρ₂gV)
3.2 = gV(ρ₂ - ρ₁)
V = \frac{3.2}{g(ρ₂-ρ₁)}
where
ρ₂ = density of water = 1000 kg/m^{3}
ρ₁ = density of ethyl alcohol = 806 kg/m^{3}
V = \frac{3.2}{9.8(1000 - 806)}
V = 1.7 x 10^{-3} m^{3}
The volume of the object can be found using Archimedes' principle and the given apparent weights in water and ethyl alcohol. The volume is computed from these values using the densities of the two fluids, yielding a volume of about 0.013 cubic meters.
Explanation:To answer the question about the object's volume when it's submerged in ethyl alcohol and water, we'll need to use Archimedes' principle. This principle tells us that the apparent weight loss of the object in a liquid equals the weight of the fluid displaced by the object. In this case, the difference in apparent weights given for the object when in water and when in ethyl alcohol represents the weight of the fluids displaced.
We have to remember that weight can be calculated as the product of volume, density, and gravity. If you rearrange this equation, you get the volume as the quotient of weight and the product of density and gravity. Note that gravity cancels out in this problem since it remains constant for both fluids.
If we denote the volume of the object as V, the density of water as ρ_water (approximated to 1000 kg/m^3), the density of ethyl alcohol as ρ_alcohol (approximated to 789 kg/m^3), and the weight of the object in water and ethyl alcohol as W_water and W_alcohol respectively, we can write two equations:
V = W_water / ρ_waterV = W_alcohol / ρ_alcoholWe have the weights as the apparent weights from the problem, which are W_water = 13.3 N and W_alcohol = 16.5 N. If you solve these two equations, you should obtain the volume of the object, which should be around 0.013 m^3. This is the answer for the volume of the solid object.
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Star-forming clouds appear dark in visible-light photos because the light of stars behind them is absorbed by __________.
Answer:
Interstellar Dust
Explanation:
In the solar system Interstellar dust is a type of cosmic dust and unlike Interstellar gas they have large dust particles enabling them to block visible light. Unlike smoke and fog, they contain large number of closely packed clumps of atoms and molecules
Answer:
interstellar dust
Explanation:
Dust particles interact with light through scattering and absorption. Reducing the amount of starlight received
The colour of the sky during the day is blue, because the blue light is scattered by atmosphere particles. The increased path length causes the change of colour of sun light . This is due to dust grains in the atmosphere, a similar process happens with interstellar dust
Who was Georges Lemaitre and how did he contribute to the Big Bang theory?
(15 points)
Final answer:
Georges Lemaître, a Belgian cosmologist, proposed the initial concept of the Big Bang, predicting the universe's expansion and Hubble's Law before they were empirically observed. His ideas on the universe starting from a 'primeval atom' and his work on particle interactions in the early universe laid the foundations of modern cosmology.
Explanation:
Georges Lemaître was a Belgian priest and cosmologist who made significant contributions to the Big Bang theory. Born in 1894, Lemaître studied theology as well as mathematics and physics. He was instrumental in exploring the concept of the expanding universe and was the first to propose a concrete model of the Big Bang. This model suggested that the universe started as a single 'primeval atom', which eventually fragmented into smaller pieces, leading to the formation of the current atoms in the universe through a process akin to nuclear fission. Lemaître's work predated and anticipated the empirical findings that became known as Hubble's Law, which observed that galaxies are moving away from each other, implying that the universe is expanding. His insights laid the groundwork for the understanding of the universe's beginnings and its initial hot, dense state.
Additionally, Lemaître, alongside collaborators such as George Gamow, further developed the Big Bang theory. They predicted that as the universe expands and cools, the interactions among particles would lead to the formation of protons, neutrons, and eventually the nuclei of light elements such as deuterium, helium, and lithium. This theoretical framework is bolstered by measurements such as the cosmic microwave background radiation and the abundance of deuterium, supporting the Big Bang theory as a robust model of the universe's inception.
Four of the wavelengths of the Balmer series occur in the visible spectrum (656 nm, 486 nm, 434 nm, and 410 nm). In which region of the electromagnetic spectrum does the fifth line, with a wavelength of 397 nm, occur?
a) X rays
b) gamma rays
c) radio waves
d) ultraviolet
e) visible light
f) infrared
g) microwaves
Final answer:
The fifth line of the Balmer series, with a wavelength of 397 nm, occurs in the ultraviolet region of the electromagnetic spectrum. Option D is correct.
Explanation:
The fifth line of the Balmer series with a wavelength of 397 nm falls into the ultraviolet (UV) region of the electromagnetic spectrum. The visible part of the spectrum ranges approximately from 380 nm to 740 nm. Since the wavelength of the fifth line is just below 400 nm, it is just outside the range for visible light and therefore must be in the ultraviolet range.
In the context of the Balmer series, there are four lines within the visible spectrum, specifically at wavelengths of 656 nm, 486 nm, 434 nm, and 410 nm. The line at 397 nm would be the first one in the UV part of the spectrum, making the answer to the student's question d) ultraviolet.
The Balmer series is a series of spectral lines in the hydrogen emission spectrum. Four of the wavelengths of the Balmer series occur in the visible spectrum: 656 nm, 486 nm, 434 nm, and 410 nm. Since the fifth line has a wavelength of 397 nm, it falls in the ultraviolet region of the electromagnetic spectrum.
When light of wavelength 345 nm falls on a potassium surface, electrons are emitted that have a maximum kinetic energy of 1.67 eV. What is the work function of potassium? The speed of light is 3 × 108 m/s and Planck’s constant is 6.63 × 10−34 J · s.
Answer:
[tex]W=1.93eV[/tex]
Explanation:
The maximum kinetic energy of an ejected electron in the photoelectric effect is given by:
[tex]K_{max}=h\nu-W(1)[/tex]
Here h is the Planck's constant, [tex]\nu[/tex] the frequency of the light and W the work function of the element.
The frequency is equal to the speed of light, divided by the wavelength:
[tex]\nu=\frac{c}{\lambda}(2)[/tex]
Recall that [tex]1nm=10^{-9}m[/tex]. Replacing (2) in (1) and solving for W:
[tex]W=\frac{hc}{\lambda}-K_{max}\\W=\frac{(4.14*10^{-15}eV\cdot s)(3*10^8\frac{m}{s})}{345*10^{-9}m}-1.67eV\\W=1.93eV[/tex]
a. At what frequency would an inductor and a capacitor have the same reactance?
b. What would the reactance be?
c. Show that this frequency would be the natural frequency of an oscillating circuit with the same L and C.
Answer:
(A.) Resonance Frequency
(B.) Totally resistance
Explanation:
A. The resonance frequency is the frequency at which the net reactance of the inductor and capacitor is zero, this is the frequency at which the capacitive reactance of the capacitor and inductive reactance of the inductor cancels each other out. Resistance is low here and the frequency is high
B. Since the net reactance of the inductor and capacitor is zero as explained in (A) above, the total reactance of the circuit will be entirely from the resistor (resistance)
A 66.0−kg short-track ice skater is racing at a speed of 10.0 m/s when he falls down and slides across the ice into a padded wall that brings him to rest. Assuming that he doesn't lose any speed during the fall or while sliding across the ice, how much work is done by the wall while stopping the ice skater?
Answer:
3300J
Explanation:
Work done is the energy that is lost by the skater
Formula for workdone = 1/2*mV^2
m = 66kg
V = 10m/s
Work done = 1/2 * 66 * 10^2
= 3300J
The work done by the wall to stop a 66.0-kg ice skater moving at 10.0 m/s is calculated using the work-energy theorem and is found to be 3300 joules.
The student is asking how much work is done by the wall to stop a 66.0-kg ice skater who is moving at a speed of 10.0 m/s. To solve this, we can use the work-energy theorem, which states that the work done on an object is equal to the change in its kinetic energy. Since the skater is coming to rest, the final kinetic energy is 0. The initial kinetic energy can be calculated using the equation KE = 0.5 × m × v^2, where m is the mass and v is the velocity. After plugging in the values, we get KE = 0.5 × 66.0 kg × (10.0 m/s)^2 = 3300 J. Therefore, the padded wall does 3300 joules of work to bring the skater to rest.
What is an extrasolar planet?
a. A planet that is considered an "extra," in that it was not needed for the formation of its solar system.
b. A planet that is extra large compared to what we'd expect.
c. A planet that is larger than the Sun.
d. A planet that orbits a star that is not our own Sun
Answer:
option (d)
Explanation:
The extra solar planet is also called as exo planet.
the planet which orbits around the star other than sun is called exo planet.
So, a planet that orbits a star that is not our own sun.
Thus, option (d) is correct.
a 74.9 kg person sits at rest on an icy pond holding a 2.44 kg physics book. he throws the physics book west at 8.25 m/s. what is his recoil velocity? PLEASE HELP ME
Answer:
His recoil velocity is 0.269 m/s to the East
Explanation:
This question is easily solved by using the law of conservation of linear momentum.
The formula for the momentum is
[tex]Mo = mv[/tex]
, where m is the mass and v its speed.
The person + the book are at rest which means their momentum is
[tex]Mo_0=0[/tex]
After the book is released, they both start to move and their combined momentum is
[tex]Mo_f=m_pv_p+m_bv_b[/tex]
Where [tex]m_p, v_p[/tex] are the mass and speed of the person respectively and [tex]m_b, v_b[/tex] are the mass and speed of the book
Knowing that
[tex]m_p=74.9 Kg, m_b=2.44 Kg, v_b=-8.25m/s[/tex] (positive speed is assumed to the right or East), and the total momentum is zero:
[tex]m_pv_p+m_bv_b=0[/tex] =>
[tex]v_p=-\frac{m_bv_b}{m_p} =-\frac{2.44 (-8.25)}{74.9}[/tex]
[tex]v_p=0.269 m/s[/tex]
Since the sign of [tex]v_p[/tex] is positive, it's directed to the East
The recoil velocity of the person after throwing the book is approximately 0.27 m/s to the east, which is the opposite direction of the thrown book.
The recoil velocity of a person after throwing an object can be found by using the principle of conservation of momentum. According to this principle, the total momentum before an event is equal to the total momentum afterwards, assuming no external forces act on the system. In this case, the person and the book together form a closed system with no external forces since they are on an icy pond, which we can consider frictionless.
The initial momentum of the system is zero because the person is at rest. After the person throws the book, the momentum of the book is mass of the book multiplied by velocity of the book. To find the recoil velocity of the person, we use the formula:
m1×u1 + m2×u2 = m1×v1 + m2×v2,
where m1 and m2 are the masses of the person and book, u1 and u2 are their initial velocities (which are zero), and v1 and v2 are their final velocities. The final velocity of the person (v1) is what we are looking for:
(74.9 kg)(0 m/s) + (2.44 kg)(0 m/s) = (74.9 kg)v1 + (2.44 kg)(-8.25 m/s),
v1 = -(2.44 kg)(-8.25 m/s) / 74.9 kg,
v1 = 0.27 m/s to the east (opposite direction to the book).
A room has a wall with an R value of 13 F sq.ft. hr/BTU. The room is 18 feet long and 8 feet wide with walls that are 8 ft high. On a particular day the average outside temperature is 31 degrees F. How much heat is transferred through the walls on that day (in BTUs)?
Answer:
Carbon electrons are arranged in a way that makes it possible for them to form long chains. That also helps carbon maintain its properties.
Explanation:
Carbon electrons are arranged in a way that makes it possible for them to form long chains. That also helps carbon maintain its properties.
A wire of length 25.0 cm carrying a current of 4.21 mA is to be formed into a circular coil and placed in a uniform magnetic field B with arrow of magnitude 5.55 mT. Suppose the torque on the coil from the field is maximized.
Answer:
1.162 x 10^-7 Nm
Explanation:
length of wire, l = 25 cm
l = 2 π r
where, r is the radius of circular loop
25 = 2 x 3.14 x r
r = 3.98 cm
Magnetic field, B = 5.55 mT = 5.55 x 10^-3 T
Current, i = 4.121 mA = 4.21 x 10^-3 A
Torque, τ = i x A x B
τ = 4.21 x 10^-3 x 3.14 x 0.0398 x 0.0398 x 5.55 x 10^-3
τ = 1.162 x 10^-7 Nm
Thus, the maximum torque in the coil is 1.162 x 10^-7 Nm.
What are the characteristics of the atmospheres of venus
Answer:
Explanation:
The atmosphere is mainly composed of Carbon Dioxide (96%), 3.5% nitrogen, and less than 1% is composed of carbon monoxide, argon, sulfur dioxide and water vapor.Venus's atmosphere is very hot and denseThe Venusian atmosphere is crossed by occasional electrical phenomena of remarkable energyThe presence of a dense atmosphere and particularly strong winds causes the surface temperature to be approximately 710-740 K throughout the planetThe atmospheric pressure on the surface reaches the value of 90 atmospheres.How many σ bonds and π bonds does the co2 molecule have?
Answer:
2 [tex]\sigma[/tex] bonds and 2 [tex]\pi[/tex] bonds
Explanation:
If we consider the the bonding in the [tex]CO_{2}[/tex] molecule:
[tex]O = 1s^{2}\ 2s^{2}\ 2p^{4}[/tex]
[tex]C = 1s^{2}\ 2s^{2}\ 2p^{2}[/tex]
Thus carbon forms double bonds with oxygen:
O = C = O
Now,
We know that double bond comprises of a [tex]\sigma\ bond[/tex] and a [tex]\pi \ bond[/tex]
Since, in the [tex]CO_{2}[/tex], there are 2 double bonds thus there are 2 [tex]\sigma[/tex] bonds and 2 [tex]\pi[/tex] bonds in the molecules.
"The CO₂ molecule has 2 σƒ (sigma) bonds and 2 π (pi) bonds.
To determine the number of sigma and pi bonds in CO₂, we need to consider its Lewis structure. Carbon dioxide has a linear molecular geometry with carbon at the center and two oxygen atoms double-bonded to it.
In CO₂:
- The carbon atom forms two double bonds with the two oxygen atoms.
- Each double bond consists of one sigma bond and one pi bond.
Therefore, for each carbon-oxygen double bond, there is:
- One sigma bond (σƒ), which is the head-on overlap of atomic orbitals.
- One pi bond (π), which is the side-to-side overlap of p-orbitals.
Since there are two carbon-oxygen double bonds in CO₂, we have:
- A total of 2 sigma bonds from the double bonds.
- Additionally, each double bond includes a sigma bond from the overlap of the sp hybrid orbital of carbon with the sp2 hybrid orbital of oxygen, contributing another 2 sigma bonds.
In summary, CO₂ has 4 sigma bonds in total:
- 2 sigma bonds from the sp-sp² hybrid orbital overlaps.
- 2 sigma bonds from the head-on overlap of p-orbitals that form part of the double bonds.
And CO₂ has 2 pi bonds in total:
- 2 pi bonds from the side-to-side overlap of p-orbitals in the double bonds.
Thus, the final count is 4 σƒ bonds and 2π bonds in the CO₂ molecule. However, it is important to note that the question specifically asks for the number of sigma and pi bonds, and the correct answer should reflect the number of each type of bond individually, not the total number of bonds. Therefore, the correct answer is 2σ bonds and 2π bonds.
A management system that includes fire suppression will likely lead to
I. large quantities of biomass accumulating on the forest floor.
II. an increase in the likelihood of uncontrolled natural fires.
III. an increase in fire-dependent species.
Answer:
I and II
Explanation:
A management system that includes fire suppression will likely lead to
I. large quantities of biomass accumulating on the forest floor.
II. an increase in the likelihood of uncontrolled natural fires.
Biomass is the total quantity of weight of flora and fauna in a given area or volume. The recent fire in the Amazon rain forest is an example of uncontrolled natural forest fires.
A 6.0 × 103 kg car accelerates from rest at the top of a driveway that is sloped at an angle of 19.3 ◦ with the horizontal. An average frictional force of 4.4×103 N impedes the car’s motion so that the car’s speed at the bottom of the driveway is 4.3 m/s. The acceleration of gravity is 9.81 m/s 2 . What is the length of the driveway? Answer in units of m.
Answer:
s = 3.68 m
Explanation:
given,
mass of the car = 6 x 10³ Kg
angle of slope with horizontal = 19.3°
Average frictional force = 4.4×10³ N
Speed of the car at the bottom = 4.3 m/s
acceleration due to gravity = 9.81 m/s²
length of driveway = ?
first calculating the net force acting on the car
F = mg sin θ - f
(mg sin θ) is the weight component of the body
(f) is the frictional force which is acting opposite to the car
F = 6000 x 9.81 x sin 19.3° - 4400
F = 19454 - 4400
F = 15054 N
we know,
Force = mass x acceleration
15054 = 6000 x a
a = 2.51 m/s²
using formula
v² = u² + 2 as
4.3² = 0² + 2 x 2.51 x s
s = 3.68 m
the length of the driveway = s = 3.68 m
Final answer:
To find the length of the driveway, we can use the equations of motion. Calculate the acceleration using trigonometry, find the net force, and use the equation v^2 = u^2 + 2as to determine the distance.
Explanation:
To find the length of the driveway, we can use the equations of motion. The acceleration of the car can be found by considering the forces acting on it. The force of gravity can be resolved into two components: one along the slope and one perpendicular to the slope. The force along the slope, which is responsible for the acceleration of the car, can be found using trigonometry. The net force acting on the car is the force along the slope minus the frictional force. We can then use the equation v^2 = u^2 + 2as, where v is the final velocity, u is the initial velocity, a is the acceleration, and s is the distance traveled, to find the length of the driveway.
Let's break the problem down step by step:
Calculate the acceleration of the car along the slope using trigonometry: acceleration = g * sin(angle).Find the net force acting on the car: net force = m * acceleration - frictional force.Use the equation v^2 = u^2 + 2as to find the length of the driveway: distance = (v^2 - u^2) / (2 * acceleration).Substituting the given values into the equations will give you the length of the driveway.