Why do perpendicular forces do No work?
Answer:
The definition of work is:
Force (dot product) distance = work
The dot product of vectors at right angles is zero - so no work can be done if the applied force is at a right angles to direction of motion
A footballer kicks a football of mass 430 g and it flies off at a speed of 8 m/s. What is the KE of the football?
Answer:
13.76 Joules
Explanation:
The SI units for joules are defined to be kilogram*meters per second. Therefore, we must turn the grams to kilograms by dividing the answer by 1,000. This is due to 1,000 grams being in a single kilogram. Kinetic energy is defined to be:
[tex]KE=\frac{1}{2} mv^2[/tex]
Therefore:
[tex]KE=\frac{1}{2} (0.43kg)(8m/s)^2=13.76J[/tex]
2. An electric motor transfers 2003 in 10.0 s. If it then transfers the same amount of energy in 8.0 s, has its
power increased or decreased?
Answer:
decreased
Explanation:
because it transfered from 10.0s
to 8.0s
A ray of light passing through centre of curvature of a concave mirror is incident on its reflecting surface. What is the angle of incidence and reflection of this ray of light?
If the height gain of each step was 0.20 m , and the mass of the runner was 69 kg , what was his average power output during the climb
Answer: 370 W
Explanation:
Find the total height
1576 steps * 0.2 metres = 315 m
Energy = mgh = 69 * 9.8 * 315
=2.12 * 10^5 J
Power = energy / time
Time = 9*60 +33 = 573 sec
So power = energy/time = 370 W
how to make a brainliest questions Or how to Get them?
Answer:
Select the crown at the bottom of an answer where the speech bubble icon is.
The energy emitted from a single photon is 1.68 x 10^-27 Joules. Which of the following is most likely the type of electromagnetic wave that was
emitted?
limiteds edition oon substartion basiss i dont kkown
A box with a total surface area of 1.2 m2 and a wall thickness of 4 cm is made of an insulating material. A 10 W electric heater inside the box maintains the inside temperature at 15 oC above the outside temperature. What is the thermal conductivity of the insulating material in units of kcal/(s oC m)
For a box with a total surface area of 1.2 m2, the thermal conductivity of the insulating material is mathematically given as
k=5.29*19^{-6} kcal/(s oC m)
What is the thermal conductivity of the insulating material?Generally, the equation for the is mathematically given as
P=Ka dT/L
Therefore
k=10*4*10^{-2}/1.2*1.5
k=5.29*19^{-6} kcal/(s oC m)
In conclusion, the thermal conductivity
k=5.29*19^{-6} kcal/(s oC m)
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The fundamental measuring unit of Electromagnetism is?
Ampere (electric current)
Volt (electric potential)
Coulomb (electric charge)
The fundamental measuring unit of electromagnetism is Ampere (electric current.Option 1 is correct.
What is electromegnetism ?The physical interplay of electric charges, magnetic moments, and the electromagnetic field is known as electromagnetism.
The electromagnetic field can be static, moving slowly, or forming waves. Electromagnetic waves are commonly referred to as light and are subject to optics laws.
The fundamental measuring unit of electromagnetism is Ampere (electric current.Option 1 is correct.
Hence option 1 is correct.
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Which circuit has the largest equivalent resistance?.
In the first direct detection of gravitational waves by LIGO in 2015, the waves came from A. the collapse of a nearby star into a white dwarf B. the merger of two black holes C. a supernova explosion in a nearby galaxy D. the rapid motion of three hot Jupiter planets around a
In the first direct detection of gravitational waves by LIGO in 2015, the waves came from the merger of two black holes. Option B is correct. This is further explained below.
What are gravitational waves?A gravitational wave is simply defined as a ripple in space that is unseen though extremely rapid. Gravitational waves move at light speed. As they pass past, these waves compress and stretch everything in their path.
In conclusion, the merger of two black holes is the first direct detection of gravitational waves.
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A weightlifter holds a barbell motionless at her chest as she prepares to lift it over her head. The work done by the weightlifter to hold the barbell in this position is
Answer:
it's a bit of a trick question
Explanation:
W = distance X force
when the distance is zero, the work is zero. So when she holds the weight without moving them she is doing no work. But, to be fair, that's just the wording, what "work" means. she is actually producing a force, that is equal to the weight of the barbells, to hold them against the graviational force.
8TH GRADE SCIENCE PLEASE HELPPP
Answer:
The two helicopters have the same kinetic energy, but a different GPE, or gravitational potential energy.
Explanation:
Laptop computers are made with batteries, but they must also be plugged into outlets to charge the batteries. which is true regarding laptops? they run only on alternating current. they run only on direct current. they can run on either direct or alternating current. they do not run on direct or alternating current.
The true statemement regarding laptops is they can run on either direct or alternating current.
What is direct current source?This is the type of current that flows only in one direction. The source of this type of current in battery.
What is alternate current source?This is the type of current that changes direction with time. The source of this type of current is current from outlet.
Thus, the true statemement regarding laptops is they can run on either direct or alternating current.
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Answer:
C
Explanation:
edge 2022
What would be the final velocity, in m/s, if a disk of the same mass and radius as the hoop rolled down the hill?.
The final velocity will be [tex]\rm V= \sqrt{\frac{4gh}{3} }\ m/sec[/tex]. Speed is a scalar quantity. It is a time-based component. Its unit is m/sec.
What is velocity?The change of distance with respect to time is defined as speed.
From the law of conservation of energy:
[tex]\rm KE_i + PE_i = KE_f+PE_f \\\\ 0+mgh = \frac{1}{2} mV^2 +\frac{1}{2} I\omega^2[/tex]
The moment of inertia of the disc;
[tex]\rm I= mr^2[/tex]
It can also be found as;
[tex]\rm I = \frac{V}{r} \\\\[/tex]
Put the obtained values;
[tex]mgh = \frac{1}{2} mv^2+\frac{1}{2} mv^2=mv^2\\\\ mgh = mv^2 \\\\ v=\sqrt{gh}[/tex]
if a disk of the same mass and radius as the hoop rolled down the hill;
[tex]mgh= \frac{1}{2} M+\frac{mr^2}{2r^2} V^2 \\\\ gh = \frac{3}{4} V^2 \\\\ V= \sqrt{\frac{4gh}{3} }\ m/sec[/tex]
Hence the final velocity will be [tex]\rm V= \sqrt{\frac{4gh}{3} }\ m/sec[/tex].
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What is the formula for principle of moments ?
Answer:
The Principle of Moments states that when a body is balanced, the total clockwise moment about a point equals the total anticlockwise moment about the same point. Moment =force F x perpendicular distance from the pivot d.
If a star has a large luminosity and also a low surface temperature then it must have:.
Answer:
To summarize, the answer is it has a small radius.
Explanation:
This is becuase these characteristics interpert a small radius.
What is the appropriate distance for social space?.
Answer:
Social distance ranges from 4 to 8 feet (1.2 m - 2.4 m) away from the person and is reserved for strangers, newly formed groups, and new acquaintances. Neuropsychology describes personal space in terms of the kinds of 'near-ness' to the body. 1.
Which space mission visited the moon several times?.
Research indicates that social isolation tends to decrease aggressive behaviors. please select the best answer from the choices provided t f
The statement "Research indicates that social isolation tends to decrease aggressive behaviors." is a False statement. This is further explained below.
What is social isolation?Generally, social isolation is simply defined as a lack of social relationships Some humans experience loneliness as a result of social isolation.
In conclusion, Social isolation does not to decrease aggressive behaviors or acts of violence.
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Answer:
false
Explanation:
9. As a cold front passes a New York weather station,
which changes will usually be observed in barometric
pressure and air temperature?
A) Pressure rises and temperature falls.
B) Both pressure and temperature rise.
C) Both pressure and temperature fall.
D) Pressure falls and temperature rises.
When the cold front or wind passes weather station, the pressure increases whereas the temperature increases.
What happen when cold front passes a New York weather station?Pressure rises and temperature falls as a cold front passes a New York weather station because wind apply pressure on the objects when they blow. If the wind is cold then the temperature decreases.
So we can conclude that when the cold front or wind passes weather station, the pressure increases whereas the temperature increases.
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Astronomers have discovered pulsars spinning 500 x per second or more. How do astronomers think pulsars got to be spinning so outrageously fast
Astronomers think pulsars got to be spinning so outrageously fast because of the stars near them, which leave substances on the pulsar.
What is pulsars spinning?Generally, Pulsars are simply defined as fast revolving neutron stars created in supernova explosions, which happen when a huge star dies and bursts.
In conclusion, This burst gives of a large amount of energy.
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Which is an example of a negative acceleration? A snowboarder who increases speed when traveling downhill, a biker who maintains a constant speed through a race
Answer:
a snowboarder who increaseds speed when traveling downhill
Explanation:
A person is attracted towards the center of Earth by a 440 N gravitational force. The force with which Earth is attracted toward the person is _____.
A person is attracted towards the center of Earth by a 440 N gravitational force. The force with which Earth is attracted toward the person is 440 N.
Reason: If you were to consider Newton's third law, it says for every action, there is an equal and opposite reaction. That means if the earth exerts a 440N force on the human, then the human will exert a 440N force on the planet.
p.s. Newton's three laws would be very helpful to know for these sorts of conceptual questions that involve forces
an object is placed 20cm from a converging lens. If the real image is formed 80cm from the object, what is the focal length of the lens?
Explanation:
Here,
object distance(u)=20cm
image distance(v)=80cm-20cm=60cm
focal length(f)=?
we know ,
(1/f)=(1/v)+(1/u)
1/f = 1/60 + 1/20
1/f = (1+3)/60
60 =4f
f=15cm
004 (part 1 of 3) 10.0 points
Two moles of helium gas initially at 410 K
and 0.47 atm are compressed isothermally to
1.34 atm.
Find the final volume of the gas. Assume
that helium behaves as an ideal gas. The
universal gas constant is 8.31451 J/K · mol.
005 (part 2 of 3) 10.0 points
Find the work done by the gas.
Answer in units of kJ.
006 (part 3 of 3) 10.0 points
Find the thermal energy transferred.
Answer in units of kJ.
The final volume of the gas, work done, and the thermal energy transferred is mathematically given as
vf=0,0623m^2
W=-4.03KJ
Q=-4.03KJ
What are the final volume of the gas, work done, and the thermal energy transferred?
Generally, the equation for the ideal gas is mathematically given as
Pv=nRT
Therefore
vf=nRT/P
vf=2*8.314330/1*1.01*10^3
vf=0,0623m^2
In conclusion
vi=nRT/Pi
vi=0.1175m^3
w=pdv
w=2*8.314*330in()0.0623/0.117
W=-4.03KJ
Where
Q=W
Q=-4.03KJ
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Who discovered the surface of venus was noxious and hot?.
The discovery that the surface of Venus is noxious and hot can be attributed to several space missions and scientific observations. However, the first confirmation of Venus's harsh conditions came from the Soviet Venera 4 mission in 1967.
Venera 4, an unmanned spacecraft, successfully descended through Venus's atmosphere and transmitted data back to Earth. The mission's instruments indicated extreme temperatures, atmospheric pressure, and the presence of noxious gases, including sulfuric acid clouds.
This groundbreaking mission provided the initial evidence that Venus has a hostile environment with a thick, toxic atmosphere and intense heat.
Therefore, it was the Soviet Venera 4 mission that played a pivotal role in confirming the noxious and hot nature of Venus's surface.
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The frequency of phenotypes for a typical polygenic trait is most often illustrated as.
Answer:
a bell-shaped curve.
Explanation:
Cognitive psychology deals with ____.
a: neutral transmissions
b: behavior influence
c: thoughts
Answer:
B
Explanation:
Because the main focus of cognitive psychology is on the metal processes that affect behavior
What must be the acceleration of a box that is pushed with 86 N of force and experiences 29 N of friction? The mass of the box is 5 kg.
Answer:
In mechanics, acceleration is the rate of change of the velocity of an object with respect to time. Accelerations are vector quantities (in that they have magnitude and direction). The orientation of an object's acceleration is given by the orientation of the net force acting on that object. The magnitude of an object's acceleration, as described by Newton's Second Law, is the combined effect of two causes: the net balance of all external forces acting onto that object — magnitude is directly proportional to this net resulting force; that object's mass, depending on the materials out of which it is made — magnitude is inversely proportional to the object's mass.
Explanation: