Answer:
Approximately [tex](-348\; {\rm J})[/tex], assuming that the bike was on level ground.
Explanation:
If an object of mass [tex]m[/tex] is moving at a speed of [tex]v[/tex], the kinetic energy of that object would be [tex](1/2)\, m\, v^{2}[/tex].
At a speed of [tex]v = 3.84\; {\rm m\cdot s^{-1}}[/tex], the kinetic energy of the bike and the cyclist- combined- would be:
[tex]\begin{aligned} &\frac{1}{2}\, m\, v^{2} \\=\; &\frac{1}{2}\times 53.0\; {\rm kg} \times (3.84\; {\rm m\cdot s^{-2}})^{2} \\ \approx \; & 390.76\; {\rm J}\end{aligned}[/tex].
At a speed of [tex]v = 1.27\; {\rm m\cdot s^{-1}}[/tex], the kinetic energy of the bike and the cyclist- combined- would be:
[tex]\begin{aligned} &\frac{1}{2}\, m\, v^{2} \\=\; &\frac{1}{2}\times 53.0\; {\rm kg} \times (1.27\; {\rm m\cdot s^{-2}})^{2} \\ \approx \; &42.741 \; {\rm J}\end{aligned}[/tex].
The energy change was approximately:
[tex]390.76\; {\rm J} - 42.741\; {\rm J} \approx 348\; {\rm J}[/tex].
If the bike was on level ground, the friction on the bike and the cyclist would have done a work of [tex](-348\: {\rm J})[/tex] to reduce the kinetic energy of the bike and the cyclist by that amount.
Answer: C) -348J
Explanation:
42.741 - 390.76 (the kinetic energy of the two speeds) is equal to -348.
Maintaining at least a 1-second space margin from the vehicle in front of you not only provides you with visibility, time, and space to help avoid rear-end crashes, but also allows you to steer or brake out of danger at moderate speeds. Select one: True False
Answer:
True -
60 mph = 60 mph * 5280 ft /hr / (3600 sec/hr) = 88 ft/sec
At 60 mph one would travel 88 ft in 1 second
Calculate the work done by a crane of power 80,000W in 60 seconds.
Answer:
48MJ
Explanation:
Formula :
Work done = Power × time
============================================================
Given :
⇒ Power = 80,000 W = 80kW
⇒ Time = 60s
=============================================================
Solving :
⇒ Work done = 80kW × 60s
⇒ Work done = 4800kJ
⇒ Work done = 48MJ (megajoule)
Our Sun has a peak emission wavelength of about 500 nm and a radius of about 700,000 km. Your dark-adapted eye has a pupil diameter of about 7 mm and can detect light intensity down to about 1.5 x 10-11 W/m2. Assume the emissivity of the Sun is equal to 1. First, given these numbers, what is the surface temperature of the Sun in Kelvin to 3 significant digits
The surface temperature of the Sun in Kelvin to 3 significant digits is 0.127 K.
Surface temperature of the Sun
The surface temperature of the sun is determined by using the following equations as shown below;
P/A = σT⁴
I = σT⁴
where;
I is intensity of the light = 1.5 x 10⁻¹¹ W/m²σ is Boltzmann constant = 5.67 x 10⁻⁸ W/m²K⁴T⁴ = I/σ
T⁴ = (1.5 x 10⁻¹¹)/ (5.67 x 10⁻⁸)
T⁴ = 2.65 x 10⁻⁴
T = (2.65 x 10⁻⁴)^¹/₄
T = 0.127 K
Thus, the surface temperature of the Sun in Kelvin to 3 significant digits is 0.127 K.
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The speed of a car increases uniformly from 6 m/s to 42 m/s in 9 second calculate the acceleration of the car
The acceleration of the car which changes the speed uniformly is 4 m/s²
What is acceleration?Acceleration can be defined as the rate change of velocity with time.
acceleration a = (Δv) / (Δt)
Given is the initial velocity 6m/s and final velocity 42m/s, the time take fir this change in speed is 9s.
Substitute the values, we have
a = (42-6)/9
a = 36/9
a =4 m/s²
Thus, the acceleration is 4 m/s²
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I want to know what is the pressure of the stratosphere simple numbers
I’m in 6 grade
Answer:
This region of increasing temperatures is the stratosphere, spanning a pressure range from 100 millibars at its base to about 10 millibars at the stratopause, the top of the layer.
Explanation:
A monkey is chained to a stake in the ground. The stake is 3.00 m from a vertical pole, and the chain is 3.40 m long. How high can the monkey climb up the pole
From the calculation and based on the Pythagoras theorem, the monkey will climb 4.5 m.
What is the Pythagoras theorem?The Pythagoras theorem is based on the sides of the right angled triangle. It states that the square of the longest side is equal to the square of the other two sides.
Thus;
c= √3^2 + 3.4^2
c = 4.5 m
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How is a simple machine different from a compound machine?
a compound machine is made of several simple machines
the difference is like a tree and a jungle
G a magnetic field perpendicular to the plane of a wire loop is uniform in space but changes with time t in the region of the loop. if the induced emf in the loop increases linearly with time t, then the magnitude of the magnetic field must be proportional to
Answer:
e = Δφ / Δt induced emf is proportional to enclosed flux
Also φ = B * A flux is proportional to area and enclosed field
If the induced emf e increases with time than the flux and hence the magnetic field is increasing with time (replace B with G)
Since e = ΔG * A / Δt if e is linear then G must also be linear and be proportional to the time
calculate the work done in kilo joules in lifting a mass of 20kg at steady velocity through a vertical height of 20m
Answer:
[tex]\huge\boxed{\sf Work\ done = 4 kJ}[/tex]
Explanation:
Since work done is in the form of potential energy, we will use the formula of potential energy here.
We know that,
P.E. = mghWhere,
m = mass = 20 kg
g = acceleration due to gravity = 10 m/s²
h = vertical height = 20 m
So,
Work done = mghWork done = (20)(10)(20)
Work done = 4000 joules
Work done = 4 kJ
[tex]\rule[225]{225}{2}[/tex]
A machine is used to convert heat energy into work energy, and is connected to a cooling system which keeps the machine at a constant temperature. If 2000 kJ of heat energy enter the machine, and the machine performs 700 kJ of work,
how much heat energy must still be removed by the cooling system?
Remember What the law of Conservation of energy says about the total energy before and after a transformation.
The amount of heat energy that must still be removed by the cooling system is 1300 kJ.
Conservation energyThe total energy before and after a transformation must be equal.
Based on this principle, the heat energy that must still be removed by the cooling system is calculated as follows;
Input heat energy = out put heat energy
E = h + w
2000 kJ = h + 700 kJ
1300 kJ = h
Thus, the amount of heat energy that must still be removed by the cooling system is 1300 kJ.
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If you know that the period of a pendulum is 1.87 seconds, what is the length of that pendulum? (assume that we are on earth and that gravity is 9.81 meters/second². ) a. 0.87 centimeters b. 2.1 meters c. 1.6 meters d. 0.87 meters e. 8.3 meters
Answer:
d. 0.87 meters
Explanation:
You want to know the length of a pendulum whose period is 1.87 seconds.
PeriodThe formula for the period of a pendulum in terms of its length is ...
T = 2π√(L/g)
LengthSolving for length, we have ...
T/(2π) = √(L/g) . . . . . . . divide by 2π
(T/(2π))² = L/g . . . . . . . square both sides
gT²/(4π²) = L . . . . . . . multiply by g
For the given period and value of g, we find the length to be ...
L = 9.81·(1.87/π)²/4 ≈ 0.87 . . . . meters
The length of the pendulum is about 0.87 meters.
Answer: d. 0.87 meters
Explanation: plato :)
the first s-wave reaches a seismic station 22 minutes after an earthquake occurred. how long did it take the first p-wave to reach the same seismic station?
The time taken for the first p-wave to reach the same seismic station is approximately 13 minutes.
Time of travel of the P-wave
In rock, S waves generally travel about 60% the speed of P waves, and the S wave always arrives after the P wave.
Relationship between speed and timev ∝ 1/t
v₁t₁ = v₂t₂
t₁/t₂ = v₂/v₁
t₁/t₂ = 0.6v₁/v₁
t₁/t₂ = 0.6
t₁ = 0.6t₂
t₁ = 0.6 x 22 mins
t₁ = 13.2 mins
Thus, the time taken for the first p-wave to reach the same seismic station is approximately 13 minutes.
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what are magnetic field line??
Answer:
Magnetic field lines are a visual tool used to represent magnetic fields.meaning you cant really see them with out the tool witch magnetic force on a north and south
Hope This Helped
Calculate the mass of air of density 1.2kgm-3 in a room of dimensions 8m by 6m by 4m.
Answer:
230.4kg
Explanation:
volume of the room = l× b×h
volume= 8×6×4
volume=192m3
density= mass/volume
hence mass= density × volume
mass= 1.2kgm-3 × 192m3
mass= 230.4kg
The earth’s orbit around the sun is elliptical. What does this word mean?.
Answer:
An elliptical orbit is the revolving of one object around another in an oval-shaped path called an ellipse. The planets in the solar system orbit the sun in elliptical orbits. Many satellites orbit the Earth in elliptical orbits as does the moon.
Nancy and Hiyang are training for a race. They entered some of their training notes in a chart.
A 3-column table with 5 rows. The first column labeled day has entries Monday, Tuesday, Wednesday, Thursday, Friday. The second column labeled Nancy's distance run has entries 2, 3, 3, 4, 5. The third column labeled Hiyang's distance run has entries 5, 5, 7, 8, 10.
Which information should be added to the chart in order find out who ran a greater distance?
the time spent running each day
the reference point used each day
the units used to measure distance each day
the location used by the runners each day
The data should be put on the graph to determine who covered a longer distance by running each day in the units that will be used to measure distance. Option C is correct.
What is the distance?Distance is a numerical representation of the distance between two objects or locations.
The distance can refer to a physical length or an estimate based on other factors in physics or common use. |AB| is a symbol for the distance between two points A and B.
Distance is measured in the meter, centimeter, miles, nautical mile, feet, etc. The unit of the distance is most important in order to find it.
Hiyang and Nancy are preparing for a race. Some of their training-related notes were entered on a chart.
The data should be put on the graph to determine who covered a longer distance by running each day in the units that will be used to measure distance.
Hence, option C is correct.
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Answer:
C) the units used to measure distance each day
Explanation:
A ball is dropped and accelerates downwards at a rate of 10m/s^2 for 12 seconds how much will the ball's velocity increase by?
Answer:
120 m/s
Explanation:
acceleration = velocity/time
10m/s^2 = velocity / 12seconds
10*12 = velocity
120m/s = velocity
When electromagnetic radiation strikes perpendicular to a flat surface
Answer:
a totally absorbing surface feels radiation pressure
Explanation:
When electromagnetic radiation strikes perpendicular to a flat surface, a totally absorbing surface feels radiation pressure
Explain the difference between average speed and average velocity. The average acceleration is the difference between the average speed and the average velocity. Average speed is measured in kilometers per hour, whereas average velocity is measured in miles per hour. There is no difference between average speed and average velocity; they are completely equivalent terms. The average speed, a scalar, is greater than or equal to the magnitude of the average velocity vector over the same time interval. The average speed, a scalar, equals the magnitude of the average velocity vector over the same time interval.
The average speed, a scalar, is greater than or equal to the magnitude of the average velocity vector over the same time interval. Option C is correct.
What is average velocity?The average velocity is the ratio of the total distance traveled to the total time taken by the body. Its unit is m/sec.
A vector is a quantity or phenomena with magnitude and direction that are independent of one another. The phrase also refers to a quantity's mathematical or geometrical representation.
The distinction between average speed and average velocity is that the scalar average speed is larger than or equal to the magnitude of the vector average velocity during the same time frame.
Hence option C is correct.
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Information about mars' moons.
Answer:
mars is a fourth planet of the sun and the second planet in the solar system
moon is a natural satellite of the earth it isthe fifth largest moon in the solar system
A airplane that is flying level needs to accelerate from a speed of 100 m/s to a speed of 260 m/s while it flies a distance of 2000 m. What must the acceleration of the plane be
When object 1 came into contact with object 2, object 2 got warmer. what can be concluded about the objects before they came into contact with each other? object 2 did not have thermal energy. object 1 had faster-moving particles. object 1 had less thermal energy. object 2 had fewer particles.
The statement that is true regarding the objects is that object 1 had faster-moving particles, which is option 2. Details about matter can be found below.
What is matter?Matter can be defined as any particle that has weight and occupies space.
Certain particles are present in the different states of matter. According to this question, when object 1 came into contact with object 2, object 2 got warmer.
This suggests that the particles in the object 1 is moving faster due to an increase in temperature.
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Answer: b
Explanation: i took the quiz
45 V =
2.0 Ω
www
6.0 Ω
3.0 Ω
>4.0 Ω
What is the equivalent resistance in this circuit?
Ω
What is the current in this circuit?
A
Answer:
Current = 22.5A
Explanation:
By using ohm's law [tex]i = \frac{v}{q} [/tex]45/2 = 22.5Angling of the focal track of the anode to create a large actual focal spot and a smaller effective focal spot describes (the):
Angling of the focal track of the anode to create a large actual focal spot and a smaller effective focal spot describes the line focus principle
What is the line focus principle?
The line focus principle states that as the anode angle is reduced, the actual focal spot also becomes small but the heat loading is increased.
It also explains the relationship between the anode surface and the effective focal spot size.
As a result of this, by angling the target, effective area of the target is made much smaller that the actual area of electron interaction.
Hence, angling of the focal track of the anode to create a large actual focal spot and a smaller effective focal spot describes the line focus principle.
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A boat going from salt water (sg = 1. 03) to fresh water (sg=1. 0) sinks 7. 82cm and after burning 72,730kg of coal rises up by 15. 24cm. Find the original displacement of the boat in seawater in kn
The original displacement of the boat in seawater in km is 7.42 x 10⁻⁵ km.
What is displacement?The shortest path traveled by any particle during its motion.
A boat going from salt water to fresh water sinks 7. 82cm. After burning coal, the boat rises up by 15. 24cm.
Displacement = 15.24 -7.82 = 7.42 cm
1cm = 10⁻⁵ km
So, 7.42 cm =7.42 x 10⁻⁵ km
Thus, the original displacement is 7.42 x 10⁻⁵ km.
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Which quantity is a vector quantity?
A.
displacement
B.
distance
C.
mass
D.
temperature
E.
volume
Answer:
Displacement...
Explanation:
Displacement is a vector quantity as it have both magnitude and direction...
[tex]...[/tex]
a. displacement is the correct answer
Displacement is a vector quantity
EXPLANATIONDisplacement is a vector quantity because it has both magnitude and direction.
Please help 40 points!!!!
choose a scientist from (democritus, john dalton, jj thomson, ernest rutherford, niels bohr, erwin schrodinger or james chadwick) . conduct research using outside sources. be sure to choose reliable resources such as government, scientific, and educational websites. document all research in your own words. be sure to properly cite all sources used in your assignment.
research and respond to the following:
what were experiences in his life that led to his interest in science and the study of the atom? (3-5 sentences paraphrased)
defend his work on the atom and its contribution to the modern atomic model. (3-5 sentences paraphrased)
point out which contributions are present in the modern atomic model and which were eventually disproven and thus are not part of the modern model. (3-5 sentences paraphrased)
works cited: list all of the websites used to find the information. you should have at least 2.
The answers to all the research related questions are written below.
What is atom?Atom is the smallest unit of the element. Different elements have different size atoms and same element have same size atoms.
James Chadwick tracked down the neutron in 1932 and was conceded the Nobel Prize for science in 1935 held in a German prison camp for all of World War 1, he driven the British gathering inside the Manhattan Extend, in which the UK and Canada maintained the USA's World War 2 effort to build the world with nuclear bomb.
Chadwick and Rutherford were the first scientists who measured the nucleus radius using the alpha particles. He did Gold foil experiment to find the size of nucleus.
The contributions are present in the modern atomic model. They are: All matter consists of atoms. Atoms of the same element are the same in size and atoms of different elements are different. Atoms combine in whole-number ratios to form compounds.
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A camera lens focuses on an
object 78.0 cm from the lens. The
image forms 3.50 cm behind the
lens. If the object is 12.4 cm tall,
how tall is the image?
(Mind your minus signs.)
(Unit = cm)
an object of 5kg is moving with a velocity of 2 m/s an externally applied force increases the velocity of an object to 6 m/s. Calculate the change in momentum
The change in momentum of an object that is initially moving at a velocity of 2m/s but later increased to 6m/s is 20kgm/s.
How to calculate change in momentum?The momentum of a body can be calculated by multiplying the mass of the body by its velocity.
However, the change in momentum is the mass of the body multiplied by the change in velocity as follows:
∆p = m × [Vf - Vi]
Where;
m = massVf = final velocityVi = initial velocity∆p = 5 × (6 - 2)
∆p = 20kgm/s
Therefore, the change in momentum of an object that is initially moving at a velocity of 2m/s but later increased to 6m/s is 20kgm/s.
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a metal block increases in tempreture from 15 digree to 60 digree when supplied with 13500 j of heat energy
By finding the specific heat, we can expect that the material of the block is copper or silver (or a mix).
Of which type of metal is the block made?We know that we give 13,500 joules of energy to the metal block (which we assume has a mass of 1kg) and the temperature increases from 15°C to 60°C.
Then the increase is:
60°C - 15°C = 45°C
Then this metal has a specific heat of:
H = 13,500j/(45°C*1 kg) = 300 J/°C*kg
So it could be copper, which has a specific heat of 380J/°C*kg or Silver, which has a specific heat of 240 J/°C*kg (or a mix of these two).
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