Answer:
12
Explanation:
avarage speed = total distance/total time
our total distance is 40km
the first 20km speed was 20km/h, so the time os 1 hour here
for the next 20km, we dont have the time, so let the time here be = x
so total time is x+1 km/h
and total distance is 40km
and the avarage is 24km/h
so =>
[tex] \frac{40}{1 + x} = 24[/tex]
solve for x to find the time in the second 20km
so x=0.6
then find the speed of the second 20km by diving the distance on time =>
[tex] \frac{20}{0.6} = 12[/tex]
so the speed in the second 20km is 12km/h
Mass of an object is 45 kg. What is its weight on the earth?(g=9.8m/s2)
[tex]\text{Weight,}~ \\\\W = mg = 45 \times 9.8 = 441~ N\\\\\text{The weight of the object on earth is 441 N}.[/tex]
what is the triboelectric effect?
Answer:
The triboelectric effect is an electrical phenomenon where certain materials become electrically charged after coming into contact with another, different, material. The polarity and strength of the charges produced differ according to material and surface smoothness.
Explanation:
The triboelectric effect causes an electrostatic charge to build up on the fur due to the cat's motions. The electric field of the charges results in a slight attraction of the light plastic pieces to the charged fur. The triboelectric effect is also the cause of static cling in clothes.
I hope this helps, if it doesn't then just message me and ill be more than happy to help :)
A manufacturer supplies plastic cups that are placed under the legs of the chair
A manufacturer supplies plastic cups that are placed under the legs of the chair. The manufacturer's claim is that there will be no marks of chair due to pushing or pulling on the floor.
Who is a manufacturer?A manufacturer is a person who converts his idea of developing and constructing any item using some set of machines.
A manufacturer supplies plastic cups that are placed under the legs of the chair.
When there is a relative motion between two objects, friction force causes the opposition to this motion. Between chair and floor, there will be high magnitude of force. But if we insert plastic cups in the legs of chair, then the friction between cup and floor will be less. This keeps the floor protected form any scratches.
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Gravitation always does negative work. question 48 options: true false
The statement indicating that 'Gravitation always does negative work' is FALSE.
What is Gravitation?Gravitation is a fundamental physical force that makes objects attract each other in the Universe.
This force (Gravitation) is required to maintain both constant positions and movement of objects.
In conclusion, the statement indicating that 'Gravitation always does negative work' is FALSE.
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Answer:false
Explanation:
During a certain chemical reaction, energy is transferred from the reaction system to its surroundings. Which statement is true in this situation? OA. The particles differ in potential energy instead of kinetic energy. B. The particles in the reaction system have more kinetic energy. C. The particles in the surroundings have more kinetic energy. OD. The kinetic energy of the particles in the system and its surroundings are the same.
The particles in the reaction system have more kinetic energy than the surroundings.
What is exothermic reaction?Exothermic reaction is a type of reaction in which energy is lost to the environment.
Internal energy (E) = kinetic energy (K.E) + potential energy (P.E)
Change in internal energy (ΔE) = K.E (particles) - K.E (surroundings)
Since energy is lost to the environment, we can conclude that the particles in the reaction system have more kinetic energy than the surroundings.
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What can be described as a technology that uses high-frequency sound waves to create images?
Answer:
Ultrasound imaging (sonography) uses high-frequency sound waves to view inside the body.
Explanation:
A forces of 5 N accelerates an object. The object’s mass is 50 g. What is the acceleration of the object? (Formula: F=ma)
Answer:
100 m / s^
F =ma from this divided F and ma by m to get acceleration
a = F / m
a = ?
F = 5 N
m = 50 g = 0. 0 5 kg ; if 1 kg = 1000g how much kg of 50 g by criss cross method we get 0.05 kg
so; 5N / 0. 05 kg = 5kg m / s^ / 0.05 kg
kg cancel by kg
the result is 100 m/ s^
L 6.3.2 Test (CST): Applications of Waves Question 5 of 10 Which event provides evidence that matter can reflect waves? O A. An audience member covers her ears during a loud concert. B. A laser beam bounces off a series of mirrors. C. A performer makes shadow puppets on a wall. D. The light from a fireworks show is seen miles away.
An audience member covers her ears during a loud concert shows evidence that matter can reflect waves.
Which event provides evidence that matter can reflect waves?An audience member covers her ears during a loud concert is an event that provides evidence that matter can reflect waves because a sound is heard again and again due to the reflection of waves. This repetition of sound is due to the property of reflection of sound waves.
So we can conclude that an audience member covers her ears during a loud concert shows evidence that matter can reflect waves.
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Answer:
A laser beam bounces off a series of mirrors
Explanation:
Which of these is true about analog signals?
1. They can capture the entire sound wave when a song is recorded on a vinyl record, resulting in a Fuller and more accurate representation of the original song.
2. A vinyl record (analog) can hold more information than a CD (digital)
3. The sound quality does not degrade when copying a vinyl record (analog) like it does for CD (digital)
PLEASE HELP LOL, I NEED TO SUBMIT THIS BEFOFE MY SCHOOL YEAR ENDS -_-
The statement true about the analog signal is they can capture the entire sound wave when a song is recorded on a vinyl record, resulting in a Fuller and more accurate representation of the original song.
What are analog signals?The analog signals are discrete in nature.
Sound can be recorded, stored and played by the use of either digital or analog techniques.
Vinyl records produces a continuous sound wave vs CDs. So, analog is more accurate,
Thus, correct option is 1.
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0.2 kg coffee cup is sitting on desk. acceleration due to gravity is 9.8m/s^2 what is the force downward exerted
[tex]~~~~~~~F = mg\\\\\implies F = 0.2 \times 9.8\\\\\implies F = 1.96~N\\\\\text{The downward force is 1.96 N.}[/tex]
In a belly-flop diving contest, the winner is the diver who makes the biggest splash upon hitting the water. the size
of the splash depends not only on the diver's style, but also on the amount of kinetic energy the diver has. consider
a contest in which each diver jumps from a 3.00-m platform. one diver has a mass of 136 kg and simply steps off
the platform. another diver has a mass of 100 kg and leaps upward from the platform. how high would the second
diver have to leap to make a competitive splash?
The second diver have to leap to make a competitive splash by 4.08 m high.
What is potential energy?The energy by virtue of its position is called the potential energy.
PE = mgh
where, g = 9.81 m/s²
Given is the diver jumps from a 3.00-m platform. one diver has a mass of 136 kg and simply steps off the platform. another diver has a mass of 100 kg and leaps upward from the platform.
The potential energy of the first diver must be equal to the second diver.
P.E₁ = P.E₂
m₁gh₁ = m₂gh₂
Substitute the vales, we have
136 x 3 = 100 x h₂
h₂ = ₂4.08 m
Thus, the second diver need to leap by 4.08 m high.
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Was this a chemical reaction? Did new products form? Make the choice that answers those questions:
The procedure is not found here but a chemical reaction is characterized to be a process where substances are converted into products.
What is a chemical reaction?A chemical reaction is a process where one or more reactants are converted into chemical products.
In a chemical reaction, enzymes are molecules that speed up the process by lowering its activation energy.
In conclusion, the procedure is not found here but a chemical reaction is characterized to be a process where substances are converted into products.
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Determine the safest option in the lab if you need your vision to be corrected. select one: wear safety goggles without any corrective lenses for the whole experiment wear safety goggles while working and switch to corrective glasses when you need to read something wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your ta or instructor for your school's policy wear your corrective glasses or lenses as normal for the whole experiment
The safest option in the lab if one need your vision to be corrected is wear corrective glasses or lenses under your safety goggles for the whole experiment, but always check with your ta or instructor for your school's policy.
What are safety goggles?When someone is performing any project in the chemistry lab, he needs to be extra care taken by himself and and the most importantly from the school. The safety goggles are used to protect the eyes from any spiling off the chemical.
One should wear corrective glasses under the safety goggles during the whole experiment.
Thus, wear corrective glasses under the safety goggles during the whole experiment.
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If i apply mascara on a roller coaster, will my eyelashes fly off or get ruined?
A student drew the following flowchart.
Crushing > Sizing > Concentrating > Dewatering
What is the purpose of the process?
A. To refine crude oil
© B. To precipitate minerals
O C. To refine minerals
O D. To blend coal
To refine minerals best describes the purpose of the process mentioned and is denoted as option B.
What is Refining?
Thi involves the different processes involved in the purification of the elements found in the earth.
Refining materials usually starts with crushing and ends with dewatering to drain water.
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The diagram shows a system in which a collision occurs between two toy cars.
What is the decrease in kinetic energy during the collision?
(A) -63 J
(B) -1.4 J
(C) -1.1 J
(D) -0.17 J
The decrease in kinetic energy during collision is 0.171 joule. Hence, option (D) is correct.
What is kinetic energy?The energy an object has as a result of motion is known as kinetic energy in physics. It is described as the effort required to move a mass-determined body from rest to the indicated velocity.
The body holds onto the kinetic energy it acquired during its acceleration until its speed changes. The body exerts the same amount of effort when slowing down from its current pace to a condition of rest.
Hence, the decrease in kinetic energy during collision =
Total initial kinetic energy - total final kinetic energy
= {1/2 × 1.15 ×(1.05)² + 1/2 ×2.25 × 0² - (1/2 × 1.15 × 0.13² + 1/2 ×1.25 × 0.85²)} Joule
= { 0.633 + 0 - 0.010 - 0.452} joule
= 0.171 joule.
Hence, The decrease in kinetic energy during collision is 0.171 joule.
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What is the relative size and composition of the universe, a galaxy, and a solar system?
The solar system is smaller than a galaxy. Galaxies are composed of solar systems. The solar system is composed of planets revolving around a star (such as our sun). To put into perspective, there are about hundreds of billions of stars in our galaxy (the milky way). On the other hand, billions of galaxies make up the universe.
The speed of light is constant which is 299 792 458 m / s. The time is taken for light to reach an object can be used to measure the distance between objects in space. This is done by multiplying the time by the speed of light.
Distance in space is so vast and therefore impractical to use the basic SI units of meters and kilometers we use here on earth. Therefore the use of astronomical units and light years is used. Light years is the distance that light can cover in a year in the vacuum of space, while astronomical units is the distance between solar systems.
.89m/s A vehicle that starts to move from the rest gets an acceleration of 5m/s² within 2 seconds. Calculate the velocity and distance covered by the vehicle within the given time. [Ans: 10m/s, 10m]
Explanation:
s = ? u = 0m/s v = ? a = 5m/s² t = 2s
v = u + at
= 0 + (5 x 2)
= 10 m/s
s = ut + 1/2 at²
= (0)(2) + x [tex]\frac{1}{2}[/tex] x 5 x 2²
= 10 m
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50 POINTS!!
What is the velocity of the mass after the force has stopped acting? only have to do question 10 but use the graph about to help. thanks!
The velocity of the mass after the force has stopped acting is 14 m/s.
What is the velocity of an object?The velocity of an object is the speed at which the object is moving in a specified direction.
Momentum is related to velocity and mass by the formula:
Momentum = mass × velocityThe velocity of the mass after 8 seconds is first determined.
Area under force-time graph = change in linear momentumChange in linear momentum = (1/2 × 2 × 6) + (6 × 4) + (1/3 ×2 × 6) = 36 kgm/s
Initial momentum = 18 kg × 12 m/s = 216 kgm/s
Final momentum = 216 + 36 = 252 kgm/s
Final Velocity = final momentum/mass
Velocity = 252/18 = 14 m/s
After 8 seconds, the force stops acting.
Therefore, the velocity of the mass after the force has stopped acting is 14 m/s.
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An inventor claims to have invented a perpetual motion machine, a machine that creates its own power and energy
allowing it to run forever. Which of the following laws best explains why this invention cannot be true?
A
the law of conservation of matter
B
the law of conservation of energy
C
newtons 3rd law
D
newtons 2nd law
Answer:
B. The law of conservation of energy
Explanation:
The law of conservation of energy states that energy can neither be created or destroyed which means that a perpetual motion machine, which creates its own power and energy, cannot be true since energy cannot be created.
Which image best represents kinetic energy?
Answer:
throwing a ball
Explanation:
because when we throw the ball we apply force so that the ball goes faster
A pendulum swings back and forth. If the mass of the pendulum is 3kg and it starts from a height of 1m.How much kinetic energy does it have at 0.5m?
From the principle of energy conservation, the kinetic energy of the pendulum at 0.5 m is 14.7 J.
What is a pendulum?A pendulum swings back and forth and can be used to show the change of potential energy to kinetic energy and vice versa.
Given that the kinetic energy is converted to the potential energy; the potential energy at 0.5 m is 3 * 9.8 * 0.5 = 14.7 J.
Following the principle of energy conservation, the kinetic energy of the pendulum at 0.5 m is 14.7 J.
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Which of the following desribes a displacement vs. time graph that looks like
this?
Time
A. constant non-zero acceleration
B. increasing velocity
C. constant velocity
D. decreasing acceleration
Why is it not possible to achieve a higher resolution in the light microscope?.
Higher resolution cannot be achieved with a light microscope because wavelength of light is larger that wavelength of electrons.
What is light microscope?Light microscope is defined as the type of microscope that makes use of visible light to magnify objects into images that can be observed.
The wavelength of light is larger than that of the electrons, therefore, higher resolution cannot be achieved with a light microscope.
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#1 explain why there is no such thing as a quick and easy way to lose weight.
#2 why can’t you not always trust “before and after” photos?
#3 what are three things you should do before you buy exercise equipment?
#4 name a exercise equipment, how it is supposed to work and why you are skeptical about it?
Exercise is a vigorous activity that tends to help us to burn calories and loose weight in the process.
What is exercise?Exercise is a vigorous activity that tends to help us to burn calories and loose weight in the process. There is no quick way to loose weight because the calories were added on gradually and must also be lost gradually.
Before and after photos does not show the loss in calories. This can only be determined by measurement.
Before you buy exercise equipment;
Ensure that the equipment meets your unique needsEnsure that you can afford itEnsure that you have enough space to contain the equipmentAn example of an exercise equipment is a stationary bicycle. It works when you sit or stand on it and cycle repeatedly though it doesn't move. I am skeptical about it because it may not help you burn a lot of calories except you use it for long periods of time.
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True or false: Scientific models are always built to scale, and are fully functional representations of the product they are testing.
Answer:
False
Explanation:
Scientific models are not always built to scale and may not be fully accurate
What is the ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2
The ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2 will be the ratio of the angular velocity.
What are comets ?Comets are frozen leftovers from the formation of the solar system composed of dust, rock, and ices.
It should be noted that the tangential speed can alternatively be represented as;
[tex]\rm v_t= r\frac{d\theta}{dt}[/tex]
where,
θ is the comet's position angle with respect to some given direction.
The amount dθ/dt is known as angular speed
The ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2 IS;
[tex]\rm \frac{v_1}{v_2} = \frac{\frac{d \theta_1}{dt_1} }{\frac{d \theta_2}{dt_2} } \\\\\ \frac{v_1}{v_2} =\frac{\omega_1}{\omega_2}[/tex]
Hence,the ratio v1/v2 of the speed of the comet at position 1 to the speed at position 2 will be the ratio of the angular velocity.
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Which type of radiation has a slightly shorter wavelength and slightly higher frequency that visible light?
Your answer:
infrared radiation
ultra-violet radiation
x-rays
radio waves
Answer:
ultraviolet radiation
For an object on a flat surface, the force of gravity is 10 newtons downward and the normal force is 10 newtons upward. The applied force is 15 newtons toward the right and the frictional force is 12 newtons toward the left. What is the magnitude and direction of the net force?
3 newtons toward the left
3 newtons upward
3 newtons downward
3 newtons toward the right
A student investigates the efficiency of a scale model of an electricity generating wind turbine using the equipment in figure 1.
the student changed the number of sales on the turbine and measures the power output from the turbine's generator. the air blower is supplied with 533w and has efficiency of 0.62.
when using two sails, the efficiency of turbine was 13%. calculate the power generated.
Based on the efficiency of the airblower of 62%, power generated by the airblower is 330.5 W.
What is efficiency of a machine?Efficiency of a machine is a ratio of the work output and the work input of a machine.
Efficiency = work output/work input × 100%The power generated by the airblower = ?
Power input to th air blower = 533 W
Efficiency = 0.62 or 62 %
Power generated by the airblower = Efficiency × work input/100
Power generated by the airblower = 62 × 533/100 = 330.5 W
Therefore, the power generated by the airblower is 330.5 W.
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