Answer:
7.5 km
Explanation:
h5 per hour means that he traveled 5 km in 1 our. And then half of the hour, which means half an hour 5 km which is 2.5.
5 + 2.5 = 7.5
or just 1.5 x 5 = 7.5
Consider a thin hoop and a uniform cylinder of equal mass and radius competing in a race down a ramp. Write a general formula for the conservation of energy for both the hoop and the cylinder.
The general formula for the conservation of energy for both the hoop and the cylinder can be expressed as: Etotal = Ekinetic + Epotential
What is energy?Energy is the capacity of a system or object to do work. It is the ability to cause change by transferring energy from one object to another. Energy can take many forms, such as kinetic energy (energy of motion), potential energy (stored energy), thermal energy (energy from heat), electrical energy (energy from the flow of electrons), chemical energy (energy stored in chemical bonds), and nuclear energy (energy stored in the nucleus of an atom).
Where Etotal is the total energy, Ekinetic is the kinetic energy and Epotential is the potential energy.
Therefore, the general formula for the conservation of energy for both the hoop and the cylinder can be expressed as:
Etotal = (1/2 mv2) + (mg * h)
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Do lighting filters use additive or subtractive properties to bring light of a certain color to our eyes?
Answer:
Different colour lights (RBG) uses additive properties to bring light of a certain color to our eyes.
Explanation:
:))
Calculate the speed for a car that went a distance of 125 miles in 2 hours time.
Answer:
65 miles per hour
Explanation:
Speed= Distance/Time
Following this formula, we just need to insert the values.
The distance is 125 miles and the time is 2 hours
125=2=65
65 miles per hour
The speed of the car was exactly 125 mi per 2 hours.
In a more familiar unit, 125mi/2hr = 62.5 mi/hr.
kinetic energy of an object is quadrupled, momentum will change by what factor?
Answer:
So as KE becomes 4times , Momentum will increase by 2 times.
__5. The study of weather patterns can predict the trajectory and intensity of this
event via satellite imagery.
A. Hurricanes
B. Tornadoes
C. Floods
D. Forest fires
Answer:
its hurricane
Explanation:
beacuse almost all the time hurricanes cause alot of trajectory in the compasses and weather maps
The study of weather patterns can predict the trajectory and intensity of hurricanes. So, option A.
What is meant by weather ?The state of the atmosphere, which includes factors such as temperature, air pressure, wind, humidity, precipitation, and cloud cover, is referred to as the weather.
Here,
Weather condition is the local climate over a specific time period, which might range from one to several weeks. Meteorological conditions are those that are characteristic for a certain place or seasons.
The study of weather and atmospheric patterns across time is known as climatology. This branch of science is devoted to observing, examining, and comprehending global weather patterns, as well as the atmospheric circumstances that lead to them.
The atmosphere's current condition can be determined by combining data from weather stations, satellites, and even data collected by aircraft.
Following that, meteorologists use what they know about atmospheric processes to predict how the atmosphere will change, so altering the weather.
Hence,
The study of weather patterns can predict the trajectory and intensity of hurricanes. So, option A.
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Enter a curve slower than the posted speed if your vehicle has a high center of gravity or if surface _____________ is less than ideal.
a. traction
b. speed
c. energy
d. maneuvers
a. traction
If your vehicle has a high center of gravity or if the surface traction is less than ideal, it is important to enter a curve slower than the posted speed. This is because vehicles with a high center of gravity or poor surface traction are more prone to instability and are more likely to roll over or lose control when negotiating sharp turns or curves at high speeds.
Traction refers to the friction or grip between the tires of a vehicle and the road surface. Poor surface traction can be caused by a variety of factors, such as wet or slippery roads, loose gravel or debris, or worn or damaged tires. When surface traction is poor, it becomes more difficult for the tires to maintain contact with the road and to transmit the forces of acceleration, braking, and steering to the road.
By entering a curve slower than the posted speed, you can reduce the lateral forces acting on your vehicle and give your tires more time to grip the road. This can help you maintain control and stability, and reduce the risk of accidents or injuries. It is important to always adjust your speed and driving style to suit the conditions of the road and the capabilities of your vehicle.
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The force of attraction between things that have mass called_____. Someone please help
The air in living room has a mass of 72 kg and a specific heat of 1010 J/(kg°C). What is the approximate change in thermal energy of the air when it warms from 15°C to 20°C?
Answer:
d
Explanation:
An object of mass m attached to a spring with constant k oscillates with amplitude A. Assuming air resistance and the mass of the spring to be negligible, which of the following changes alone would cause the period of this oscillation to increase?
I. Increasing m
II. Increasing A
III. Using a spring with greater k
I only
II only
I or II only
I, II, and III
II or III only
The correct option is A, Increasing the mass m will increase the period of oscillation.
Oscillation refers to the repetitive back-and-forth motion of a physical system around a central equilibrium position. This type of motion is exhibited by many different systems in physics, including mechanical systems such as springs, pendulums, and vibrating strings, as well as electrical systems such as circuits and radio waves.
The behavior of oscillating systems can be described mathematically using equations that govern the motion of the system over time. These equations typically involve parameters such as frequency, amplitude, and phase, which determine the characteristics of the oscillation. Oscillations can have many different applications in physics, including the measurement of time, the production and detection of sound and light waves, and the generation of electrical signals.
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How many meters across is a road sign that has an angular size of 120 arcseconds and is 1 km away?
For a certain transverse standing wave on a long string, an antinode is at x = 0 and an adjacent node is at x = 0.20 m. The displacement y(t) of the string particle at x = 0 is shown in the figure, where the scale of the y axis is set by ys = 4.3 cm. When t = 0.90 s, what is the displacement of the string particle at (a) x = 0.30 m and (b) x = 0.40 m ? What is the transverse velocity of the string particle at x = 0.30 m at (c) t = 0.90 s and (d) t = 1.3 s?
The expressions for the traveling and standing wave to find the results for the questions about the displacement and speed of the particle are:
a) For time zero, the displacement at position x = 0.30 m is y = 3.04 cm
b) For time zero, the displacement at position x = 0.40 m is: y = 0
c) For the point x = 0.30 and time t = 0.9s, the velocity of the particle is:
v = 9.11 cm / s
d) For the point x = 0.30 and time t = 1.3s, the velocity of the particle is:
v = 9.65 cm / s
The traveling wave is a disturbance in the medium that moves at constant speed, in the case of a transverse wave the expression for the perpendicular oscillation is:
y = A sin (kx - wt)
Where y is the oscillation perpendicular to the direction of the displacement, A the amplitude, k in wave number and w the angular velocity.
Standing waves are formed when a traveling wave collides with an obstacle and is reflected, in this case the sum of the two waves gives a wave that does not shift in time and fulfills the relationship
\(\frac{\lambda}{2} = \frac{L}{n}\)
Where λ is the wavelength, L the distance between the reflection points and n the number of nodes.
Indicates that for the standing wave the distance between an antinode and the node is x = 0.20 m, therefore
\(\frac{\lambda}{4} = \frac{L}{1}\)
λ = 4L
λ = 4 0.20
λ = 0.80 m
The wave number.
k = \(\frac{2\pi }{\lambda }\)
k = \(\frac{2 \pi }{0.80 }\)
k = 2.5π i m⁻¹
In the associated traveling wave, from the graph we can see that the period of the wave is:
T = 2.8 s
the angular velocity is related to the period.
\(w=\frac{2\pi}{T} \\w = \frac{2\pi }{2.8}\)
w = 0.714π rad/s
indicate the maximum displacement that is the amplitude of the wave.
A = \(y_s\)
A = 4.3 cm
Let's write the equation of the traveling wave.
y = 4.3 sin [π (2.5 x - 0.714 t)]
with this expression we can answer the questions.
a) the displacement of the particle for x = 0.30 m
y = 4.3 sin (π (2.5 0.30 - 0.714 t))
y = 4.3 sin π( 0.75 - 0.714 t(
Remember that the angles must be in radians. For time t = 0 the displacement is
y = 4.3 0.707
y = 3.04 cm
b) The displacement for x = 0.4m
y = 4.3 sin (π 2.5 0.4)
y = 0 cm
c) the transverse velocity of the wave at x = 0.30 m for the time of t = 0.90s
the speed of the wave is
\(v= \frac{dy}{dt} \\v= A w cos ( kx - wt)\)
v = 4.3 0.714π cos π(2.5 0.3 - 0.714 t)
v = 9.65 cos π(0.75 - 0.714 t)
For time t = 0.90 s the velocity is:
v = 9.65 cos π(0.75 - 0.714 0.9)
v = 9.65 0.9436
v = 9.11 cm / s
d) The velocity for time t = 1.3 s
v = 9.65 cos π(0.75 - 0.714 1.3)
v = 9.65 0.9999
v = 9.65 cm / s
In conclusion, using the expressions for the traveling and standing wave, we can find the results for the questions about the displacement and speed of the particle are:
a) For time zero, the displacement at position x = 0.30 m is y = 3.04 cm
b) For time zero, the displacement at position x = 0.40 m is: y = 0
c) For the point x = 0.30 and time t = 0.9s, the velocity of the particle is:
v = 9.11 cm / s
d) For the point x = 0.30 and time t = 1.3s, the velocity of the particle is:
v = 9.65 cm / s
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Only mirrors reflect light? True or false?
False - Every object which is not transparent and translucent reflect light. In order to see colours, the object absorb light and reflect the light we see.
Mathias is going to do some informational interviewing. What is one of the main benefits of doing these interviews?
O A.
OB.
O C.
O D.
A.He will gain insight about a new career opportunity.
B.He will likely be offered a position with a company.
C.He will be able to ask questions about job openings.
D.He will find out how much money everyone earns.
Answer:
A
Explanation:
One of the main benefits of informational interviewing is that it allows the person conducting the interviews to gain insights and information about a particular career or industry.
The mechanical advantage of a wheel and axle is the radius of the wheel divided by the radius of the axle.
What is the mechanical advantage of the wheel and axle shown below?
A .16
B. 24
C. 6
D. 12
E. 17.5
The mechanical advantage for the given question is 6, as the mechanical advantage of a wheel and axle is equal to the radius of the wheel divided by the radius of the axle.
What benefit does the wheel and axle system have mechanically?The ratio of the force generated by a simple machine to the force applied to it is known as mechanical advantage. By only comparing the radius of the wheel to the radius of the axle and applying the formula Ma=Rw/Ra to the situation of the wheel and axle, the mechanical advantage can be determined.
What does rotational mechanical advantage entail?The ratio of the wheel's radius to the axle's radius is what gives the wheel and axle their mechanical advantage.
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Calculate the momentum of at 1500 kg car traveling at 6 m/s?
Answer:
Explanation:
momentum =mass*speed
p=1500 kg*6 m/s
p=9000 kgm/s
What is the electric potential energy of the group of charges in the figure? (Figure 1)
that the relative placements of the charges as well as their multiples affect a set of ions' potential energy. When the specific charge have the same sign or have equal signs, the energy is positive. Or else, it is negative.
How is potential energy calculated?The force acting just on two objects affects the potential energy formula. The formula for gravitational force is P.E. (= mgh, where g seems to be the acceleration caused by gravity (9.8 m/s2 at the earth's surface) while h represents the elevation in metres.
What is a system with two charges' potential energy?As a result, the system's potential energy equals the sum of a work that was done to set up the entire system of two counts. The potential energy that exists in the combination of two charges in such an external field can be stated as follows: q1V(r1) = q2V(r2) + (q1q2/4or12).
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A roller coaster is at a peak of 20m and has a mass of 900kg. What is the potential energy of the roller coaster?
O 100000 J
10000 J
O 9.8 J
O 176400 J
The potential energy of the roller coaster is 176,400 J (joules).
The potential energy of an object is given by the formula PE = mgh, where PE is the potential energy, m is the mass of the object, g is the acceleration due to gravity, and h is the height or vertical position of the object.
In this case, the roller coaster is at a peak of 20m and has a mass of 900kg. The acceleration due to gravity, g, is approximately 9.8 \(m/s^2\).
Using the formula, we can calculate the potential energy:
PE = mgh
= (900 kg)(9.8 \(m/s^2\))(20 m)
= 176,400 J
Therefore, the potential energy of the roller coaster is 176,400 J (joules).
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chemical name and a common name for NaOH
the common name of sodium hydroxide is causyic soda
The radius of a circle of area A and circumference C is doubled. find the new circumference of the circle in terms of C.
If the radius of a circle of area A and circumference C is doubled, the new circumference of the circle, in terms of C, will be equal to 2C.
The area (A) of a circle is given by:
\( A = \pi r^{2} \) (1)
And a circumference (C) is:
\( C = 2\pi r \) (2)
Where:
r: is the radius
If the radius of a circle and circumference is doubled, the new circumference of the circle is:
\( C_{2} = 2 (2 \pi r) = 2C \)
Therefore, the new circumference of the circle in terms of C is equal to 2C.
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A 35.30-kg box is attached to a light string that is wrapped around a cylindrical frictionless spool of radius 10.0 cm and moment of inertia 4.00 kg * m^2. The spool is suspended from the ceiling, and the box is then released from rest a distance from rest a distance 3.50 m above the floor. How long does it take for the box to reach the floor?
Answer:
The velocity of the box is related to the angular velocity of the spool, which is given by the equation:
v = r * ω
where r is the radius of the spool and ω is the angular velocity of the spool. The angular velocity of the spool, in turn, is related to the torque applied to the spool by the tension in the string, which is given by the equation:
τ = I * α
where τ is the torque, I is the moment of inertia of the spool, and α is the angular acceleration of the spool.
The tension in the string is equal to the weight of the box, which is given by:
T = m * g
Putting all of these equations together, we can solve for the time it takes for the box to reach the floor. Here's how:
First, we can find the angular acceleration of the spool using the torque equation:
τ = I * α
T = m * g = τ
m * g = I * α
α = (m * g) / I
α = (35.30 kg * 9.81 m/s^2) / 4.00 kg*m^2
α = 86.53 rad/s^2
Next, we can find the angular velocity of the spool using the kinematic equation:
ω^2 = ω_0^2 + 2 * α * θ
where ω_0 is the initial angular velocity (which is zero), θ is the angle through which the spool has turned (which is equal to the distance the box has fallen divided by the radius of the spool), and ω is the final angular velocity (which is what we want to find). Solving for ω, we get:
ω^2 = 2 * α * θ
ω = sqrt(2 * α * θ)
ω = sqrt(2 * 86.53 rad/s^2 * (3.50 m / 0.10 m))
ω = 166.6 rad/s
Finally, we can find the time it takes for the box to reach the floor using the equation:
v = r * ω
v = 0.10 m * 166.6 rad/s
v = 16.66 m/s
t = d / v
t = 3.50 m / 16.66 m/s
t = 0.21 s
Please help!!!!!!!
A tennis racket hits a tennis ball forward by exerting a force of 55 N on the ball.
What force does the ball exert on the tennis racket during the hit?
A. The ball exerts an equal backward force on the racket.
B. The ball is light, so it exerts almost no force on the racket.
C. The ball causes drag on the racket with a small forward force as it flies away.
D. The ball exerts a smaller force that alternates forward and backward to vibrate the racket.
Motion can be described in terms of the speed, position, velocity, and acceleration of an object. How do these quantities relate to one another?
Speed is defined as a change in position over time. Position's derivative is velocity, and velocity's derivative is acceleration.
What is the relation between speed, position, velocity , acceleration?The speed equation is as simple as distance divided by time. We can define Speed as the rate at which an object's position changes in any direction.S = d/t
The direction is also indicated by the position function.In these problems, you're usually given a position equation of the form " x=" or " s (t) = s(t)= s(t)=", which tells you how far an object is from a given reference point.v = v 0 + a t
The velocity of something is the rate at which it moves in a specific direction.Although speed and velocity are frequently used interchangeably, they are distinct concepts in physics. The equation,v = s/t
represents velocity (v) as a vector quantity that measures displacement (or change in position, s) over time (t). A point or object moving in a straight line is accelerated if it accelerates or decelerates. Even if the speed is constant, motion on a circle is accelerated because the direction is constantly changing.a = (v - v0) / t = Δv / t
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POSSIBLE POINTS: 100
What is the frequency of a wave that has a period of 0.32 seconds? Show all work and use correct units of measure
Answer: \(f=3.125 Hz\)
Explanation:
frequency = 1 / period
\(f=\frac{1}{T}\)
\(f=\frac{1}{0.32}=3.125Hz\)
Therefore, the frequency of the wave is 3.125 Hz.
10. Explain why a power plant doesn’t make electricity.
Answer: The power station converts stored chemical energy in the fuel to kinetic energy in the raised temperature of the steam that pushed a turbine to rotate the generator that makes electricity.
So chemical to thermal (kinetic) to thermal to kinetic to electrical. Then mostly to heat or movement.
Loads of losses, thermal, mostly.
Explanation: hopes this helps
In all of the power plants, electricity is generated by rotating turbine inside a magnetic field. That is why, power plant transfers mechanical energy into electric energy. That is why, it doesn’t make electricity.
What is power plants?
An industrial facility for the production of electricity is referred to as a power plant. In most cases, power plants are wired into a grid.
A revolving device called a generator, which transforms mechanical power into three-phase electric power, is found in many power plants. An electric current is produced by the movement of a conductor in relation to a magnetic field.
The majority of power plants throughout the world produce electricity by burning fossil fuels including coal, oil, and natural gas. Nuclear energy and the usage of renewable energy sources including solar, wind, geothermal, and hydroelectricity are examples of low-carbon power sources.
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A rock weighing 250N falls from a height of 16 m and falls towards the ground. Determine the momentum of the rock prior to striking the ground.
Answer: I'm not very good at all. I need help with determine the velocity of an object just before it hits the ground, given the object's mass and the distance it falls. For example, a .060 kg (or 60 g) ball falls from a 12 meter building. Also, assume it is free falling (no air resistance) and the average time it takes to hit the ground it 1.16 seconds.
Explanation:
with an armature resistance of 0.03 2 and a field resistance of
41.67 2. The motor has compensating windings, so armature
reaction can be ignored. Mechanical and core losses may be
assumed to be negligible for the purposes of this problem. The
motor is assumed to be driving a load with a line current of 126 A
and an initial speed of 1103 r/min. To simplify the problem,
assume that the amount of armature current drawn by the motor
remains constant.
A. If the machine's magnetization curve is shown in Figure 8-9, what is the motor's
speed if the field resistance is raised to 50 ?
B. Calculate and plot the speed of this motor as a function of the field resistance RF
assuming a constant-current load.
R₁ = 0.03 2
EA
IA
IF
IL
RF + Radj
LF
+
250 V
A. The motor's speed is approximately 1086 r/min if the field resistance is raised to 50 Ω.
B. The speed of this motor as a function of the field resistance RF is approximately 1086 r/min
A. According to the magnetization curve shown in Figure 8-9, the motor's speed can be calculated by using the following equation:
EA = kϕN, where EA is the back EMF, k is a constant, ϕ is the magnetic flux, and N is the motor speed.
Since the amount of armature current remains constant, the back EMF is also constant.
Therefore, the magnetic flux must also be constant. The magnetic flux is proportional to the field current IF, which can be calculated using Ohm's law:
IF = (250 V - EA)/(RF + R₁)
At the initial field resistance of 41.67 Ω, the field current is IF = (250 V - EA)/(41.67 Ω + 0.03 Ω) = (250 V - EA)/41.70 Ω.
If the field resistance is raised to 50 Ω, then the new field current is IF = (250 V - EA)/(50 Ω + 0.03 Ω) = (250 V - EA)/50.03 Ω.
Since the magnetic flux is constant, we can set the two expressions for IF equal to each other and solve for N:
kϕN/IF1 = kϕN/IF2
N = (IF2/IF1)N1 = (250 V - EA)/(50.03 Ω + 0.03 Ω) * 1103 r/min ≈ 1086 r/min
Therefore, the motor's speed is approximately 1086 r/min if the field resistance is raised to 50 Ω.
B. The speed of the motor as a function of the field resistance RF can be plotted using the same equation used in part A:
N = (250 V - EA)/(RF + R₁ + Radj) * 1103 r/min
where Radj is the resistance of any additional resistance in the circuit. Since the load current is constant, the current through the motor is also constant, so EA is also constant.
Therefore, the speed is inversely proportional to the total resistance in the circuit, which includes the field resistance RF, armature resistance R₁, and any additional resistance Radj.
A plot of the speed as a function of the field resistance is shown in Figure 8-10. As the field resistance increases, the speed of the motor decreases due to the increased total resistance in the circuit. This relationship is linear for this type of constant-current load.
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The first ionization potential for calcium (Z = 20, A = 40) is 6.11 eV. Singly-ionized calcium (Ca+) produces two very strong absorption lines in the Sun’s spectrum discovered by Joseph Fraunhofer in 1814, who named them "H" and "K" (he didn’t know they were from calcium, as this was >100 years before the development of quantum mechanics). Both lines always appear together, with lambda subscript H equals 3968 end subscript Å and lambda subscript K equals 3933 Å; hence they are called a "doublet
A. What is the speed of an electron that has just barely enough kinetic energy to collisionally ionize a neutral calcium atom? What is the speed of a calcium ion with this same kinetic energy?
B. What is the temperature T of a gas in which the average particle energy is just barely sufficient to ionize a neutral calcium atom?
C. The lower energy level of both lines is the ground state of Cat. What is the difference in energy in eV) between the two states that correspond to the upper energy levels of the Hand Klines, respectively? How does this compare to the energy of a calcium K photon? Can these two lines can be formed by transitions to upper energy levels with different principal quantum numbers (different n), or do they represent transitions with the same n but some different higher-order quantum number? Explain your reasoning based on your understanding of the general behavior of atomic energy levels (En).
Answer:
A) v = 1.47 10⁶ m / s, v = 0.5426 10⁴ m / s , B) T = 4.7 10⁴ K, C) n₂ = 42
Explanation:
A) For this part, let's calculate the speed of an electron that has an energy of 6.11 eV.
Let's reduce the units to the SI system
E₀ = 6.11eV (1.6 10⁻¹⁹ J / 1eV) = 9.776 10⁻¹⁹ J
The kinetic energy of the electron is
K = ½ m v²
E₀ = K
v = √ 2E₀ / m
v = √ (2 9.776 10⁻¹⁹ / 9.1 10⁻³¹)
v = √ (2.14857 10¹²)
v = 1.47 10⁶ m / s
now the speed of a calcium ion is asked, let's find sum
m = 40 1.66 10⁻²⁷ = 66.4 10⁻²⁷ kg
v = √ (2E₀ / M)
v = √ (2 9.776 10⁻¹⁹ / 66.4 10⁻²⁷)
v = √ (0.2994457 10⁸)
v = 0.5426 10⁴ m / s
B) the terminal energy of an ideal gas is
E = 3/2 kT
T = ⅔ E / k
T = ⅔ (9,776 10-19 / 1,381 10-23)
T = 4.7 10⁴ K
C) To calculate the energy of these lines we use the Planck expression
E = h f
where wavelength and frequency are related
c =λ f
f = c /λ
let's substitute
E = h c /λ
let's look for the energies
λ = 396.8 nm
E₁ = 6.63 10⁻³⁴ 3 10⁸ / 396.8 10⁻⁹
E₁ = 5.0126 10⁻¹⁹ J
λ = 393.3 nm
E₂ = 6.63 10⁻³⁴ 3 10⁸ / 3.93.3 10⁻⁹
E₂ = 5.0572 10⁻¹⁹ J
The difference in energy between these two states is
ΔE = E₂ -E₁
ΔE = (5.0572 - 5.0126) 10⁻¹⁹ J
ΔE = 0.0446 10⁻¹⁹ J
let's reduce eV
ΔE = 0.0446 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹ J)
ΔE = 2.787 10⁻² eV
Now let's use Bohr's atomic model for atoms with one electron,
E = -13.606 Z² / n²
where 13,606 eV is the energy of the base state of the Hydrogen atom, Z is the atomic number of Calcium
n = √ (13.606 Z² / E)
λ = 396.8 nm
E₁ = 5.0126 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹J) = 3.132875 eV
n₁ = √ (13.606 20² / 3.132875)
n₁ = 41.7
since n must be an integer we take
n₁ = 42
λ = 393.3 nm
E₂ = 5.0572 10⁻¹⁹ J (1eV / 1.6 10⁻¹⁹ J) = 3.16075 eV
n₂ = √ (13.606 20² / 3.16075)
n₂ = 41.5
Again we take n as an integer
n₂ = 42
We can see that the two lines have the same principal quantum number, so for the difference of these energies there must be other quantum numbers, which are not in the Bohr model, because of the small difference they are possibly due to small numbers of the moment angular orbital or spin
A 66.1-kg boy is surfing and catches a wave which gives him an initial speed of 1.60 m/s. He then drops through a height of 1.59 m, and ends with a speed of 8.51 m/s. How much nonconservative work (in kJ) was done on the boy?
A 66.1-kg boy is surfing and catches a wave which gives him an initial speed of 1.60 m/s. He then drops through a height of 1.59 m, and ends with a speed of 8.51 m/s. The nonconservative work done on the boy is approximately -42.7 kilojoules.
To find the nonconservative work done on the boy, we need to consider the change in the boy's mechanical energy during the process. Mechanical energy is the sum of the boy's kinetic energy (KE) and gravitational potential energy (PE).
The initial mechanical energy of the boy is given by the sum of his kinetic energy and potential energy when he catches the wave:
E_initial = KE_initial + PE_initial
The final mechanical energy of the boy is given by the sum of his kinetic energy and potential energy after he drops through the height:
E_final = KE_final + PE_final
The nonconservative work done on the boy is equal to the change in mechanical energy:
Work_nonconservative = E_final - E_initial
Let's calculate each term:
KE_initial = (1/2) * m * v_initial^2
= (1/2) * 66.1 kg * (1.60 m/s)^2
PE_initial = m * g * h_initial
= 66.1 kg * 9.8 m/s^2 * 1.59 m
KE_final = (1/2) * m * v_final^2
= (1/2) * 66.1 kg * (8.51 m/s)^2
PE_final = m * g * h_final
= 66.1 kg * 9.8 m/s^2 * 0
Since the boy ends at ground level, the final potential energy is zero.
Substituting the values into the equation for nonconservative work:
Work_nonconservative = (KE_final + PE_final) - (KE_initial + PE_initial)
Simplifying:
Work_nonconservative = KE_final - KE_initial - PE_initial
Calculating the values:
KE_initial = (1/2) * 66.1 kg * (1.60 m/s)^2
PE_initial = 66.1 kg * 9.8 m/s^2 * 1.59 m
KE_final = (1/2) * 66.1 kg * (8.51 m/s)^2
Substituting the values:
Work_nonconservative = [(1/2) * 66.1 kg * (8.51 m/s)^2] - [(1/2) * 66.1 kg * (1.60 m/s)^2 - 66.1 kg * 9.8 m/s^2 * 1.59 m]
Calculating the result:
Work_nonconservative ≈ -42.7 kJ
Therefore, the nonconservative work done on the boy is approximately -42.7 kilojoules. The negative sign indicates that work is done on the boy, meaning that energy is transferred away from the boy during the process.
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a car travels at the speed of 117km/h.How far will the car travels in 50 minutes
Answer:
117/60*50
Explanation:
Trust me bc I'm smart
Which statements describe scientific laws but not theories or hypotheses? Check all that apply.
They are likely to change as new evidence is discovered.
They do not provide explanations for why they are true.
They are considered to be proven facts.
They have not yet been tested.
They are the bases for experiments instead of the results.
Answer:
B. They do not provide explanations for why they are true.
C. They are considered to be proven facts.
Explanation:
edge 2021
The statements describe scientific laws but not theories or hypotheses are they do not provide explanations for why they are true and they are considered to be proven facts.
What are scientific laws?The law given by the experimenters or scientists after years of observations and experiments based on the scientific reasons are called scientific laws.
The laws are not the proven facts. They even don't explain why the scientific laws are true.
Thus, the correct option is B and C.
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