Assignments
1. A shopper pushes a grocery cart 20.0 m at constant speed on level ground, against a 35.0 N
frictional force. He pushes in a direction 25.0" below the horizontal. (a) What is the work done
on the cart by friction? (b) What is the work done on the cart by the gravitational force? (c)
What is the work done on the cart by the shopper? (d) Find the force the shopper exerts, using
energy considerations. (e) What is the total work done on the cart?
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A) What is the work done?
Answer: We need to use the formula
[tex]w=-F_f(d)[/tex]
[tex]w=-(35)(20)[/tex]
[tex]w=-700J[/tex]
B) What is the work done on the cart by the gravitational force?
Alright, we know that the gravitional force is perpendicular to the diplacement. Therefore, we gonna use the following formula:
[tex]w=Fdcos90[/tex]
[tex]w=0[/tex]
C) What is the work done on the cart by the shopper?
This is the easier part, since we already know that the work done by the shopper is the same as the work done by the friction force
[tex]W shopper + W friction = 0\\W shopper = W-friction \\W shopper = 700J[/tex]
D) Find the force the shopper exerts, using energy considerations.
[tex]F_f+Fcos25=0\\-35+Fcos25=0\\F=38.6N[/tex]
E) What is the total work done?
You just need to add them:
[tex]w=wshopper+wfriction\\w=0[/tex]
What does it mean to be a carrier?
Which of the following statements is correct about air temperature?
1. When air temperature is higher, the weather is warmer.
2. Warm air falls to the ground.
3. Freezing air temperatures increase the chances of rain.
4. When air temperature is higher, the weather is colder.
Explanation:
Warm air falls to the ground
The statement that is correct about air temperature is when the air temperature is higher, the weather is warmer. The correct option is 1.
What is air temperature?A measurement of the air's heat or cold is its temperature. It is the weather parameter that is most frequently measured.
The kinetic energy, or energy of motion, of the gases that make up air, is more explicitly described by temperature. The temperature rises as gas molecules move more swiftly.
Surface temperatures are typically hotter than air temperatures. Parking your car in the sun is an illustration of this. The air inside the car will be fairly close to the outside air temperature and you may leave the windows down and yet have excellent ventilation.
Therefore, the correct option is 1. When the air temperature is higher, the weather is warmer.
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what is ionisation?
Answer: Ionisation is the process of an atom gets a negative or a positive charge by gaining or losing electrons. The result is an ion.
Explanation: Thats why
9. When we see the color of an object it absorbs all of the light colors except? _________________
The color it reflects The color it absorbs White light
it absorbs all ligj colour except black
What would the acceleration of a car be from a stoplight if it started at 0 m/s and reached a
speed of 100 m/s in 7.8 seconds?
Answer:
The acceleration of a car would be: [tex]a=12.8[/tex] m/s²
Explanation:
Given
Initial velocity = [tex]v_1=0[/tex] m/s
Final velocity = [tex]v_f=100[/tex] m/s
Time elapsed = [tex]t = 7.8[/tex] s
To determine
We need to determine the acceleration of a car.
We know that acceleration is basically the rate of change in velocity over time.
Thus,
We can determine the acceleration using the formula
[tex]\:\:\:a=\:\frac{v_f-v_i}{t}[/tex]
where
[tex]a[/tex] is the acceleration[tex]v_1[/tex] is the initial velocity[tex]v_f[/tex] is the final velocity[tex]t[/tex] is time elapsednow substituting the values [tex]v_1=0[/tex], [tex]v_f=100[/tex], and [tex]t = 7.8[/tex] in the formula
[tex]\:\:\:a=\:\frac{v_f-v_i}{t}[/tex]
[tex]a=\:\frac{100-0}{7.8}[/tex]
[tex]a=\frac{100}{7.8}[/tex]
[tex]a=12.8[/tex] m/s²
Therefore, the acceleration of a car would be: [tex]a=12.8[/tex] m/s²
percent of Earth's surface is made up of Oxygen.
a) 30
b) 46
c) 62
Answer: it's made up about 21% so if you do not have this option I say go with 30
Explanation:
What causes a liquid to freeze? A. When particles speed up and get closer together. B. When particles stop moving. C. When particles slow down and get closer together. D. When particles speed up and get farther apart.
Answer:The answer is C
Explanation:
Why does the chord of an electric heater not glow while the heating element does
Answer:
The heating element of the heater is made up of alloy which has very high resistance so when current flows through the heating element, it becomes too hot and glows red. But the resistance of cord which is usually of copper or aluminum is very low so it does not glow.
An element carries a_____charge
Answer:
The charge of an element is equal to the number of protons minus the number of electrons. The number of protons is equal to the atomic number of the element given in the periodic table. The number of electrons is equal to the atomic number minus the charge of the atom.
Explanation:
Answer:
hydrogen sometimes has a charge of zero or (less commonly) -1. Although noble gas atoms almost always carry a charge of zero, these elements do form compounds, which means they can gain or lose electrons and carry a charge.
Explanation:
What are the half lives for uranium-235 and uranium-238?
a.
The half-life of uranium-235 is 713 seconds, the half-life of uranium-238 is 4.5 minutes
c.
The half-life of uranium-235 is 713,000,000 years, the half-life of uranium-238 is 4,500,000,000 years
b.
The half-life of uranium-235 is 713 days, the half-life of uranium-238 is 450 days
d.
None of the above
Answer:
C. The half-life of uranium-235 is 713,000,000 years, the half-life of uranium-238 is 4,500,000,000 years
How many kgs are in 1000N?
Answer:
this much I think 101.9716212978
Answer:
approximately 102kg
Explanation:
1 kg on the surface of the Earth weighs 9.80665 N
1000 N = 1000/9.80665 kg = 102 kg
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calculate the pressure exerted on the floor when an elephant who weighs 2400N stands on one foot which has an area of 0.4m squared
Answer:
6000pa
Explanation:
force= 2400N
area= 0.4m
pressure=?
now,
p= f/a
p= 2400/ 0.4
therefore,P=6000 pa.
An object has a kinetic energy of 25 J and a mass of 34 kg, how fast is the object moving?
6th grade science pls help
Answer:
D
Explanation:
I hope you get a good grade!
Is there a difference in how a black shirt or a white shirt affects our exposure to us radiation?
How much mass can be lifted by a weight lifter on the surface of the moon if he can lift 100 kg on the Earth?
Answer:
if u have to find mass then it always constant everywhere that is 100kg but if u have to find weight then it 1/6 of earth .
Explanation:
16.6666
a ball rolled a velocity of 20m/s after 5s it comes to stop what is the acceleration of the ball
Answer:
please find the attached pdf
Explanation:
can you suggest improvement that can be made towards the design of siphon so that the transfer of liquid is much higher.
Answer:
A siphon is a tube that makes use of the potential energy of fluid at an elevated level to transfer the fluid to a lower level, due to pressure differences between the inlet and the outlet points of the tube, such that the pressure at the outlet is higher than the pressure at the inlet
The pressure energy is converted into velocity (kinetic) energy, and therefore, in other to increase the flow rate through the tube of a siphon, with constant diameter, the level of the fluid in the container at the inlet (supply) of the siphon is raised higher than the level at the outlet receiving) container or the outlet point of the siphon tube
The larger the difference between the inlet and outlet levels, the faster the transfer of fluid by the siphon
Explanation:
Blake strikes a punching bag with 80N of force for 0.05 seconds. John strikes a
punching bag with 60N of force for 0.1 second. Who delivers a greater amount of
impulse?
Answer:
So impulse= force × timeP1= 80N× 0.05 = 4 P2= 60N × 0.1= 6 Hence John delivers a greater impulse I do exams and quizzes if your interestedProblem 1. A 70-kg person standing on a frictionless platform of ice throws a football
forward with a velocity of 12m/s. If the person moves backward (sliding) with a velocity of
34cm/s, what is the mass of the football?
Problem 2. A car traveling at 8m/s crashes into a car of identical mass stopped at a traffic
light. What is the velocity of the wreckage immediately after the crash, assuming that the
cars stick together?
Problem 3. A 30-kg child stands on a frictionless surface. Th father throws a 0.8-kg football
with a velocity of 15m/s. What velocity will the child have after catching the football?
Problem 4. A billiard ball moving to the left at 30 cm/s collides head with another ball
moving to the right at 20cm/s. The masses of the balls are identical. If the collision is
perfectly elastic, what is the velocity of the first ball after impact if velocity of the second
ball is 4cm/s toward the right?
Problem 5. Two metal balls A and B are suspended, as shown in the figure, so that each
touches the other. The masses are given in the figure. Ball A is pulled to the initial side until it
is 12 cm above its initial position, and then it is released. If it strikes ball B in a completely
elastic collision, find the height h reached by ball B assuming zero friction.
Answer: The answer is in your heart
Explanation: I don't know, just trust °_°
It depends on the location on the periodic table and if it is easier to loose are gain electrons to fill the valence electron shell.
What is the electron affinity?The electron affinity of the neutral atom of the element can show indicate whether or not the element is going the make positive or negative ions. The higher the electron affinity is, the more the neutral atom wants to gain electrons.
The electron affinity for alkali metals and alkaline earth metals are low due to the fact that they are located on the left of the periodic table and only needs to loose 1 or 2 electrons to have a completed valence shell.
That means that they want to form cations (loose electrons). Halogens have a high electron affinity since they are located on the right of the periodic table and only have to gain 1 electron to get a completed valence electron configuration. That means that it forms anions.
Therefore, It depends on the location on the periodic table and if it is easier to loose are gain electrons to fill the valence electron shell.
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is an increase in speed in a certain time .
a. Acceleration
b. ActionReaction Pairs
c. Force
d. Inertia
It's Acceleration
We can calculate the average speed by finding the total distance traveled divided by the elapsed time: Average speed=–s=Total distanceElapsed time. Average speed = s – = Total distance Elapsed time.
1. A stone is thrown upwards with an initial velocity of 25 m/s at angle of 30° to the ground a. Show that the vertical component if the velocity at the starting is 12.5 m/s upwards.
The vertical component of the velocity at the starting is 12.5 m/s upwards.
What is velocity?Velocity is the direction at which an object is moving and serves as a measure of the rate at which its position is changing as seen from a specific point of view and as measured by a specific unit of time.
In kinematics, the area of classical mechanics that deals with the motion of bodies, velocity is a fundamental idea.
Given that stone is thrown upwards with an initial velocity of 25 m/s at angle of 30°.
Hence, the vertical component of the velocity in upward direction = 25 sin30° m/s
= 25 × 1/2 m/s
= 12.5 m/s.
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A car driving at a constant velocity of 15 m/s has what acceleration? PLEASE HELP
Answer:
32
Explanation:
The electromagnetic spectrum is divided into regions by Group of answer choices a.wavelengths and frequencies b.the way they are used c.speed d.colors
Answer:
Generally, by wavelengths and frequencies.
Colors only occur for a narrow portion of the spectrum.
The speed for these waves is c the speed of light regardless of wavelength.
The way they are used seems somewhat irrelevant.
The electromagnetic spectrum is divided into regions by wavelengths and frequencies. The spectrum is arranged in the order of increasing frequency.
What is electromagnetic spectrum ?The electromagnetic spectrum is the arrangement of waves in the order increasing frequency or decreasing wavelength. The order of the spectra starts from radio waves, microwaves, infrared, visible light, ultraviolet, x -rays and gamma rays.
The visible light that we can see is in between IR and UV rays. Hence, visible light has a frequency greater than IR rays but shorter than IR. Similarly visible light is longer than UV- rays but less frequency than UV rays.
Gamma rays are the most energetic and shorter waves in the electromagnetic spectrum with smaller wavelength and greater frequency. Hence, options a is correct.
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The power generated by the engine was just 2.984 KW. How long would this engine have to run to produce 3.60 × 104 J of work?
1 watt = 1 joule/second
1 KW = 1,000 joule/second
Work = (power) x (time)
3.6 x 10⁴ J = (2,984 joules/second) x (time)
time = (3.6 x 10⁴J) / (2,984 J/s)
time = (36,000J) / (2,984 J/s)
time = 12.06 seconds
A 615 watt refrigerator runs 24 hours/day. How much energy is used per month (30 days)?
Answer:
14.76
Explanation:
If you put it in the calculator it would show
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Answer:
B
Explanation:
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Qué estudios se realizan en la actualidad para utilizar la electricidad de una manera más eficiente?
Answer:
Se realizan estudios en tres áreas: a) Procesos de transformación de la energía, b) Almacenamiento de la energía, c) Gestión inteligente entre consumo y generación.
Explanation:
Actualmente, se están realizando estudios en principalmente en tres áreas cruciales: a) Procesos de transformación de la energía, b) Almacenamiento de la energía, c) Gestión inteligente entre consumo y generación.
a) Se están desarrollando nuevos materiales que permiten mayor eficiencia entre la energía recibida y la energía eléctrica, además de una mayor durabilidad frente a las condiciones ambientales. Esto implica el mejoramiento del desempeño de las tecnologías basadas en las energías renovables y limpias, acortando su brecha con las energías no renovables.
b) Se están desarrollando nuevos materiales que garanticen una mayor densidad energética y mayor durabilidad, significando baterías más compactas, con mayor capacidad y más competitivas económicamente.
c) Se están desarrollando estrategias de control inteligente a tiempo que permite sincronizar el consumo y la generación, además de posibilitar el flujo bidireccional de la energía a través de una red inteligente (smart grid) e integrar mejor las fuentes renovables dentro de la matriz energética.
A concrete dam holds back a large reservoir of water
potential or kinetic energy
Answer:
The water in a reservoir behind a hydropower dam is another example of potential energy. The stored energy in the reservoir is converted into kinetic energy as the water flows down a large pipe called a penstock and spins a turbine.
Explanation:
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A concrete dam holds back a large reservoir of water potential energy, the stored potential energy is converted into the kinetic energy which is converted into mechanical energy and then further converted into electrical energy.
What is hydropower?A dam or other construction that alters the natural flow of a river or other body of water is used to generate hydropower, often known as hydroelectric power.
In order to generate energy, hydropower uses the perpetual, never-ending water cycle, which uses water as a fuel and leaves no waste products behind. Although there are many different kinds of hydropower plants, they are always propelled by the kinetic energy of water moving downstream.
Thus, a concrete dam holds back a large reservoir of water potential energy.
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