An 80 kg skier stands at the top of a 40-meter slope. She then skis down the slope. What is her approximate speed at the bottom of the slope if friction is negligible and her kinetic energy is 31360 J?

Answers

Answer 1

Thank you for that information.  If we know her mass and kinetic energy, then we don't need any of that other business about the height of the slope, her skiing ability, the friction of the snow, what she uses to wax her skis, the color of her parka, or what she had for lunch at the chalet.  The mass and kinetic energy are enough to answer the question.

Kinetic Energy = (1/2) · (mass) · (speed)²

31,360 J = (1/2) · (80 kg) · (speed)²

speed² = (31,360 J) / (40 kg)

speed² = 784 m²/s²

speed = 28 m/s


Related Questions

What is a curved line in velocity time graph represent?

Answers

A curved line shows the slope is constantly changing. Think about it - an upward curve shows the slope is pretty flat at first but it gets very steep as time increases.

So what is the slope of a Vt graph represent? Well, slope is rise over run, aka delta V over delta t. That’s just the formula for acceleration.

We know the slope is changing, and the slope is acceleration, therefore we can say that the acceleration is changing.

It turns out that if you graph this changing acceleration with time, the acceleration changes at a constant rate - it’s linear, NOT a curve. (If you have specific values you could plot this, but if you’re just talking about general graphs, then just take my word for it).

In summary - if you’re velocity is changing at a non constant rate, then you’re acceleration must be changing (at a constant rate).

Hope this helped!

1. How much electrical energy is needed to bring two charges Q1= 5.5 x 10-7C and Q2= 1.7 x 10-6 C from infinity to where they are 1 meter apart.

Answers

Answer:

The electrical energy needed is 8.415*10⁻³ N

Explanation:

Energy is the ability of a body to make changes or work.

By separating or joining two electric charges a distance (for example, a radius r) within their electric fields, you are taking away or giving the electric charges energetic potentials, relative to each other. By releasing these charges, they will attract or repel each other, releasing that acquired electrical energy.

In other words, electric potential energy is linked to the particular configuration of a conglomerate of point charges in a defined system.

That is, it calculates the capacity of an electrical system to carry out a task based exclusively on its position or configuration. So, it is a kind of energy stored in the system, or the amount of energy that it is capable of delivering.

Thus, a charge will exert a force on any other charge and the potential energy is the result of the set of charges.

The electric potential energy that has a point charge q in the presence of another point charge Q that are separated by a certain distance r is:

[tex]Ep=K*\frac{Q1*Q2}{r^{2} }[/tex]

where:

Ep is the electric potential energy. It is measured in Newton (N). Q1 and Q2 are the values ​​of the two point charges. They are measured in Coulombs (C). r is the value of the distance that separates them. It is measured in meters (m). K is the constant of Coulomb's law. For vacuum its value is approximately 9*10⁹ N*m²/C²

In this case:

Q1=5.5*10⁻⁷ CQ2=1.7*10⁻⁶ Cr=1 m

Replacing:

[tex]Ep=9*10^{9}\frac{N*m^{2} }{C^{2} } *\frac{5.5*10^{-7}C *1.7*10^{-6}C }{(1m)^{2} }[/tex]

Solving:

Ep= 8.415*10⁻³ N

The electrical energy needed is 8.415*10⁻³ N

The electrical energy is needed to bring two charges Q1 and Q2 from infinity to where they are 1 meter apart is 8.415 x 10⁻³ N.

What is the electric potential?

An electric potential can be defined as the amount of work or energy needed to move a charge from one point to another against the electrical field.

We know that in order to know electrical energy is needed to bring two charges Q1= 5.5 x 10⁻⁷C and Q2= 1.7 x 10⁻⁶ C from infinity to where they are 1 meter apart, we need to calculate electric potential energy between the two charged particles,

[tex]E_P = k\dfrac{Q_1Q_2}{d^2}[/tex]

Substitute the values,

[tex]E_P = 9 \times 10^9 \dfrac{5.5 \times 10^{-7} \times 1.7 \times 10^{-6}}{1^2}\\\\E_P = 8.415 \times 10^{-3}\rm\ N[/tex]

Hence, the electrical energy is needed to bring two charges Q1 and Q2 from infinity to where they are 1 meter apart is 8.415 x 10⁻³ N.

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What does it mean to be a carrier?

Answers

One that transports or conveys: baggage carriers; a message carrier. 2. One, such as a person, business, or organization, that deals in the transport of passengers or goods. 3. A mechanism or device by which something is conveyed or conducted.

6th grade science pls help

Answers

Answer:

D

Explanation:

I hope you get a good grade!

An object has a kinetic energy of 25 J and a mass of 34 kg, how fast is the object moving?

Answers

It moves about 1,21 m/s

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.

Answers

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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is an increase in speed in a certain time .

a. Acceleration
b. ActionReaction Pairs
c. Force
d. Inertia

Answers

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.

Which orbital is the first to fill with electrons in a given principal energy level?

Answers

Answer:

s orbital

Explanation:

that the answer

Why does the chord of an electric heater not glow while the heating element does​

Answers

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.

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?

Answers

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 elapsed

now 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

Qué estudios se realizan en la actualidad para utilizar la electricidad de una manera más eficiente?

Answers

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 ball rolled a velocity of 20m/s after 5s it comes to stop what is the acceleration of the ball​

Answers

Answer:

please find the attached pdf

Explanation:

pls help i’ll give brainliest if you give a correct answer!!

Answers

Answer:

B

Explanation:

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state and explain the joules law​

Answers

Answer:

Joule’s law of heating states that when a current ‘i ' passes through a conductor of resistance ‘r’ for time ‘t’ then the heat developed in the conductor is equal to the product of the square of the current, the resistance and time.

H = i 2 rt

The reason behind the heat produced is the collision of the free electrons with the lattice ions or atoms while accelerating in presence of the external electric field.

we know that

volt= work done/ total charge or v = w/q

from this we get w= vq

we know that current i = q / t

so q = it

putting this in prev equation

we get w = vit

from ohms law v = ir

putting it in prev eq we get

w = irit = i2rt joule as work is stored as heat soH = I2RT Joules

if a current carrying conductor having resistance (r) gets heated by to passing of current (i) for time (t) and the heat thereby produced be H

joules law states that

H propotional to i^ 2 when r and t are constant

H propotional to r when I and t are constant

H propotional to t when r and I constant

percent of Earth's surface is made up of Oxygen.
a) 30
b) 46
c) 62

Answers

Answer: it's made up about 21% so if you do not have this option I say go with 30

Explanation:

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.

Answers

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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A 615 watt refrigerator runs 24 hours/day. How much energy is used per month (30 days)?

Answers

Answer:

14.76

Explanation:

If you put it in the calculator it would show

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?​

Answers

Hello there!

I hope you and your family are staying safe and healthy during this unprecendented time.

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]

]A net force of 15 N is applied to a cart with a mass of 2.1 kg.How long will it take the cart to travel 2.8 m, starting from rest? Acceleration=7.14m/s²

Answers

we will use one of the kinematic equations :

d = u*t+0.5*a*t²

in which : d : distance

u : initial velocity

a : acceleration

t : time

after substitution :

initial velocity = 0 m/s (from rest)

2.8 = 0*t+0.5*7.14*t²

2.8 = 3.57*t²

t² = 0.7843

after square root

t = 0.885615 s

I hope this answer will help

a load of 600 kg is lifted by a carne up to 60 meters in 6 minutes . calculate it work and power.​

Answers

Explanation:

work=force*distance. force=load/10

___________

work=60*60=3600n

power=work/time(seconds)

Powe required is 1000

Explanation:

-Given: M= 600kg               H: 60

-Time of operation: t = 6 min = 360 seconds

-Work done in lifting boxes: w= mgh (600 x 10 x 60) = 360,000

-Power required: p=[tex]\frac{w}{t} = \frac{360000}{360} = 1000[/tex]

Put the following objects in order from smallest
Wrong order
Milky Way
Earth
Moon
Jupiter
Universe
Sun
Comet
Solar System

Answers

Moon

Earth

Sun

Comet

Jupiter

Solar system

Milky Way

Universe

Which situation involves kinetic energy being transformed into sound energy?

Answers

Answer:

c

Explanation:

this is because you move ( kinetic energy) your hands and clap the other person's hand, you will definitely hear sound right.

Answer:

c

Explanation:

When they move their hands together their energy transforms to sound energy.

Is there a difference in how a black shirt or a white shirt affects our exposure to us radiation?

Answers

There is a difference of exposure to radiation to a black shirt and a white shirt but I think the difference is so insignificant that it’s not even considered different. The effects of radiation wearing a dark colored shirt on a sunny day to humans is probably not significantly different enough to warrant not wearing your favorite band tee out of fear you will get radiation poisoning.
But there is definitely a difference in heat. If you insist on wearing a black shirt and you want to avoid having a heat stroke then you should probably consider bringing water, maybe an extra shirt and sun screen if you have to be outside for more than 10-15 minutes.
Under the sun, the black shirt absorbs all wavelengths (more light). A white shirt reflects the visible light that hits it.
heat follows the same laws of conservation of light energy. This means light energy and heat cannot be created or destroyed. The light and heat has to go somewhere.
The light doesn’t cause the heat but they follow the same rules so instead of visually seeing the lack of light, you feel the heat energy that is being absorbed by your shirt.
you are exposed to the same amount of radiation wearing a black shirt as you are the white shirt. The difference is the “color” (because some people don’t consider black and white a color) and how light reacts to it.

I hope I was able to help!! This was a great question :)!!

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?

Answers

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

How many kgs are in 1000N?​

Answers

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

giving me brainliest will make my day

A car driving at a constant velocity of 15 m/s has what acceleration? PLEASE HELP

Answers

Answer:

32

Explanation:

An element carries a_____charge

Answers

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:

Three identical resistors have an equivalent resistance 15.6 ohm when they are connected in series. What is the resistance for each resistor

Answers

Answer:

5.2 Ω.

Explanation:

What is the resistance for each resistor

Since the resistors are connected in series and each have resistance R, and their equivalent resistance is R' = 15.6 Ω.

Since they are connected in series, R' = R₁ + R₂ + R₃

Since R₁ = R₂ = R₃ = R

R' = R + R + R = 3R

R' = 3R

R = R'/3

R =  15.6 Ω/3

R =  5.2 Ω

So, the resistance of each resistor is 5.2 Ω.

What is the kinetic energy of the ball as it is half way through the fall?

Answers

Therefore, the kinetic energy of the ball will be equal to the potential energy of the ball at minus the potential energy of the ball at . i.e. It is a common sense as the ball has fallen halfway, half of its potential energy is converted into the kinetic energy

can you suggest improvement that can be made towards the design of siphon so that the transfer of liquid is much higher.​

Answers

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:

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