A washing machine heats 10kg of water in each wash cycle. How much energy is saved by washing at 30'c instead of 50'c if the starting temperature of the cold water is 16'c? The specific heat capacity of water is 4200 J/Kg'c

Answers

Answer 1

Answer:

[tex]8.4 \times 10^{5}\; \rm J[/tex], assuming that there's no heat exchange between the washing machine and the environment.

Explanation:

Let [tex]m[/tex] denote the mass of water and [tex]c[/tex] the specific heat capacity of water. The energy required to raise the temperature of that much water by [tex]\Delta T[/tex] would be:

[tex]Q = c \cdot m \cdot \Delta T[/tex].

Washing at [tex]30\; \rm ^{\circ} C[/tex] would require a temperature change of [tex]\Delta T = 30\; \rm ^{\circ} C - 16\; ^{\circ} \rm C = 14\; \rm K[/tex].

Washing at [tex]50\; \rm ^{\circ} C[/tex] would require a temperature change of [tex]\Delta T = 50\; \rm ^{\circ} C - 16\; ^{\circ} \rm C = 34\; \rm K[/tex].

In both situations, [tex]c = 4.2 \times 10^{3}\; \rm J \cdot kg \cdot K^{-1}[/tex] while [tex]m = 10\; \rm kg[/tex].

Calculate the energy required in either situation:

Washing at [tex]30\; \rm ^{\circ} C[/tex]:

[tex]\begin{aligned}& Q({30\; ^{\circ} {\rm C}}) \\ &= c \cdot m \cdot \Delta T \\ &= 4.2 \times 10^{3}\; \rm J \cdot kg \cdot K^{-1} \times 10\; \rm kg \times 14\; \rm K \\ &= 588000 \times 10^{5}\; \rm J\end{aligned}[/tex].

Washing at [tex]50\; ^{\circ} {\rm C}[/tex]:

[tex]\begin{aligned}& Q({50\; ^{\circ} {\rm C}}) \\ &= c \cdot m \cdot \Delta T \\ &= 4.2 \times 10^{3}\; \rm J \cdot kg \cdot K^{-1} \times 10\; \rm kg \times 34\; \rm K \\ &= 1428000 \; \rm J\end{aligned}[/tex].

[tex]1428000\; \rm J - 588000\; \rm J = 8.4 \times 10^{5}\; \rm J[/tex].


Related Questions

Can any1 tell if my answer is right

Answers

Answer:

The correct answer would be C. 5.0kg

Explanation:

The mass of an object never changes unless parts of the object are taken away. In other words, although the gravitational force is different on the moon then on the earth the mass of the object would remain the same.

a galaxy that is a featureless spherical ball of stars would be called a type

Answers

Answer:

E0

Explanation:

Yes. The "0" indicates that it is spherical

This is not meant to be a long, mathematically-intensive problem. If you find yourself going down that road, you might want to rethink your approach.

Answers

Answer:

rethink your approach to what?

Explanation:

Using techniques similar to the aluminum foil lab, how could you do an experiment to determine the volume of the filled soda bottle? What factors might limit the accuracy of your experiment?

Answers

Answer:

applications of density measurements. The densities of brass and aluminum will be calculated from mass and volume measurements.

Explanation:

A(n) 1700 kg car is moving along a level road at 21 m/s. The driver accelerates, and in the next 10 s the engine provides 22000 J of additional energy. If 3666.67 J of this energy must be used to overcome friction, what is the final speed of the car

Answers

The final speed of the car at the given conditions is 30.1 m/s.

The given parameters:

Mass of the car, m = 1700 kgVelocity of the car, v = 21 m/sTime of motion, t = 10 sAdditional energy provided by the engine, E₁ = 22,000 JEnergy used in overcoming friction, E₂ = 3,666.67 J

The change in the energy applied to the car is calculated as;

[tex]\Delta E = E_1 - E_2\\\\\Delta E = 22,000 \ J \ - \ 3,666.67 \ J\\\\\Delta E = 18,333.33 \ J[/tex]

The final speed of the car is calculated as follows;

[tex]\Delta E = \frac{1}{2} m(v_f^2 - v_0^2)\\\\v_f^2 - v_0^2 = \frac{2\Delta E}{m} \\\\v_f^2 = \frac{2\Delta E}{m} + v_0^2\\\\v_f = \sqrt{ \frac{2\Delta E}{m} + v_0^2} \\\\v_f = \sqrt{ \frac{2\times 18,333.4}{1700} + (21)^2} \\\\v_f = 30.1 \ m/s[/tex]

Thus, the final speed of the car at the given conditions is 30.1 m/s.

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Ali kicks a soccer ball upward at 45° angle
with an initial speed of 32 m/s. What
expression should Ahmed use to calculate
the magnitude of the ball's initial velocity
the horizontal direction?

Select one:
a. 32 sin(45°) m/s

b. 32 cos(45°) m/s

c. 32 tan(45°) m/s

d. 45 m/s

Answers

Answer:

the answer is 32sin(45°)m/s

2 questions, 100 points

Gravitational force between objects ____________ as objects move farther apart, and it is ___________ between objects that are closer together.
increases, weaker
increases, stronger
decreases, weaker
decreases, stronger

In science, weight is measure in

Pounds
Kelvin
Newtons
Liters

Answers

1. Is decreases, stronger
2. Pounds

Answer:

decreases, stronger

newtons

Explanation:

write down 4 situations where magnets are used in our daily life​

Answers

Answer:

Magnets are used to make a tight seal on the doors to refrigerators and freezers

They power speakers in stereos, earphones, and televisions

Magnets are used to store data in computer's

magnets are used in the compass

What is the current in a 120V circuit if the resistance is 20Ω?

Answers

We have: [tex]I=\frac{U}{R}=\frac{120}{20}=6A[/tex]

ok done. Thank to me :>

Answer:

The Current is 6 Ampere.

Step-by-step explanation:

Given :

[tex]\small\red\bull[/tex] Voltage = 120V[tex]\small\red\bull[/tex] Resistance = 20Ω

To Find :

[tex]\small\red\bull[/tex] Current

Using Formula :

[tex] \star{\small{\underline{\boxed{\sf{ I = \dfrac{V}{R}}}}}}[/tex]

[tex]\small\blue\star[/tex] I = Current[tex]\small\blue\star[/tex] V = Voltage[tex]\small\blue\star[/tex] R = Resistance

Solution :

Substituting all the given values in the formula to find Current :

[tex]{\dashrightarrow{\pmb{\sf{ I = \dfrac{V}{R}}}}}[/tex]

[tex]{\dashrightarrow{\sf{ Current = \dfrac{Voltage}{Resistance}}}}[/tex]

[tex]{\dashrightarrow{\sf{ Current = \dfrac{120}{20}}}}[/tex]

[tex]{\dashrightarrow{\sf{ Current = \cancel{\dfrac{120}{20}}}}}[/tex]

[tex]{\dashrightarrow{\sf{ Current = 6A}}}[/tex]

[tex]{\star{\underline{\boxed{\sf{\red{ Current = 6A}}}}}}[/tex]

Hence, the Current is 6 Ampere.

[tex]\rule{300}{1.5}[/tex]

Write a paragraph explaining how a pressurized garden sprayer works. Make sure todescribe what happens to the air pressure insidethe sprayer as it is pumped by hand.

Answers

The principle of operation of a pressurized garden sprayer is as follows;

A pressurized garden sprayer is a chamber which is filled with a liquid which can be a lubricant, paint or chemical, then filled with compressed air to allow the liquid to be sprayed at high pressure.

As it is pumped by hand, the compressed air with which it is filled serves the primary purpose of allowing the liquid to be sprayed at high pressure - an important requirement for performance characteristics of the sprayer.

Flammable liquids must not be used with such equipment.

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a measure of change in velocity in a measure of time is

Answers

[tex]\\ \sf\Rrightarrow Acceleration=\dfrac{\Delta V}{t}[)tex]

In simplified form

[tex]\\ \sf\Rrightarrow Acceleration=\dfrac{dv}{dt}[/tex]

The rate of change of velocity with respect to time period is called acceleration.SI units-m/s^2

Over a period of 2.50 seconds, a speedboat accelerates uniformly from 18.5 m/s to 46.5 m/s. What is the acceleration of the speedboat relative to the shore?

Answers

The answer is : 11.2 m/s2

According to the question, the acceleration of the speedboat relative to the shore is found to be 11.2 [tex]m/sec^2.[/tex]

What is Acceleration?

Acceleration may be characterized as the rate of change of the velocity of an object with respect to time. It is a vector quantity, as it defined both magnitude and direction. This allows you to measure how fast velocity changes in meters per second squared (m/s^2).

According to the question,

The initial velocity of the boat = 18.5 m/s.

The final velocity of the boat = 46.5 m/s.

Difference in velocity = Final velocity - Initial velocity = 46.5-18.5 = 28 m/s.

The formula for calculating the acceleration of the boat is as follows:

a = Difference in velocity/time taken.

           = 28/2.50 = 11.2 [tex]m/sec^2[/tex].

Therefore,  the acceleration of the speedboat relative to the shore is found to be 11.2 [tex]m/sec^2.[/tex]

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What important role does each play in an exercise regiment?

Answers

Answer: There are five principles of fitness out of which two are overload principle and rest and recovery principle. Overload principle is one of the most important principle which tell that to gain and improve the fitness one should do the hard work.  

Slowly and gradually the intensity and time of exercise are increased so that our body can adapt to the hard work. Overload principle plays an important role in improving the skills and improving performance during exercise and sports.

Rest and recovery principle is important to relax the body and release the stress that happens due to intense training like in case of weight lifting one day rest should be taken to repair and rebuild the muscles. This allows the body to encounter the fatigue and improve performance.

Explanation:

. What material does sound move quicker through?
Water
Air
Steel

Answers

Answer:

steel

Explanation:

the close molecules in solids allows sound to travel at a faster speed

Sound will move quicker through Steel than in water and air.

Sound: This can be defined as an audible form of energy, that is radiated outward from a source.

⇒ Generally,

Sound wave travels fastest in solid,  more than in liquid or gas. This is because the molecules of solid are more closely together.

⇒ From the question above,

Water is a liquid materialAir is a gaseous materialSteel is a solid material

Therefore, sound will move quicker through Steel than in water and air.

Hence: sound will move quicker through Steel than in water and air.

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A rectangular room twice as long as it is wide would contain 145 square feet more if each side were one foA rectangular room twice as long as it is wide would contain 145 square feet more if each side were one foot longer. What is the length of the room

Answers

The length of the room is 96 ft.

Let L be the length of the room and W be the width of the room.

Since the length is twice its width, L = 2W.

Its area A = LW

= 2W × W

= 2W²

If each side were increased by 1 foot, then its new area is A' = (L + 1)(W + 1)

= (2W + 1)(W + 1)

= 2W² + 3W + 1

Since the room would contain 145 ft more if each side were increased by 1 foot, then its new area is A' = A + 145 = 2W² + 3W + 1

2W² + 145 = 2W² + 3W + 1

145 = 3W + 1

3W = 145 - 1

3W = 144

W = 144/3

W = 48 ft.

Since its length L = 2W, substituting W = 48 into the equation, we have

L = 2(48)

L = 96 ft

So, the length of the room is 96 ft.

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What’s 5.1 cm in Newton’s?

Answers

0.051 newton meter.

batman recharges his bat taser with 2500 joules of energy in 15 minutes. how much power does it draw from the mains

Answers

The power P in watts (W) is equal to the energy E in joules (J), divided by the time period t in seconds (s):
P(W) = E(J) / t(s)

2.78 Watts

If your friend was on a skateboard and you pushed them with forward (away from your) with a force of 15N, would you feel a force? If so, how much and what direction? *

Answers

Yes. Newton’s third law of motion states every action has an equal and opposite reaction. You would feel a force of 15 N and you would go backwards. This is all assuming you were on a skateboard or were on something where you could move.

Yes.  you would feel a force 20 N towards backward direction due to this.

What is force?

The definition of force in physics is: The push or pull on a massed object changes its velocity.

An external force is an agent that has the power to alter the resting or moving condition of a body. A spring balance can be used to calculate the Force. The Newton is the SI unit of force.

"When one body exerts a force on the other body, the first body experiences a force that is equal in size in the opposite direction of the force which is exerted," according to Newton's third law of motion.

Hence, according to Newton's third law of motion, when you pushed them with forward (away from your) with a force of 15N, you would feel a force of equal magnitude (20 N) in opposite direction (backward direction).

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A car travels 120 miles in 12 hours. What is
the car's speed?

Select one:
O a. 10 m/s

b. 10 mph

c. 1200 mph

O d. 0.1 m/s

Answers

Answer:

I hope it will help you...

#CARRYONLERANING

effect of looping the loop​

Answers

Answer:

What does this mean? please provide more explanation when asking for help

When traveling north from the United States into Canada, you'll see the North Star (Polaris) getting _________. lower in the sky higher in the sky dimmer brighter

Answers

When traveling north from the United States into Canada, you'll see the

North Star (Polaris) getting higher in the sky .

This is because the polaris which is also known as North Star is located

very close to the north celestial pole. When an objects moves towards the

north , the polaris gets higher due to its upward northern location.

This is the major reason why when traveling north from the United States

into Canada, you'll see the North Star (Polaris) getting higher.

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Answer:

Higher

Explanation:

As you go further north, the Star Polaris rises in the sky. This is due to it being circumpolar meaning that the star doesn't move in the night sky (Often)

Twins Bo and Joe have a combined mass of 200 kg and are zooming along at 10 m/s in a 100 kg amusement park bumper car. They bump into Melinda’s car, which is sitting still. Melinda has a mass of 25 kg and is also in a 100 kg car. After the collision, the twins continue moving with a speed of 4.12 m/s.
a. What is the initial momentum of the system?
b. What must be the final momentum of the system?
c. How fast is Melinda’s car bumped across the floor?

Answers

The speed with which Melinda’s car is bumped across the floor is 14 ms-1.

Total mass of the twins and the car = 300 Kg

Initial velocity of the twins car =  10 m/s

Total mass of Melinda and her car = 125 Kg

Initial velocity of Melinda's car = 0 m/s (at rest)

Final velocity of the twins car =  4.12 m/s

Final velocity of Melinda's car = ?

Initial momentum of the system = (300 × 10) + (125 × 0) = 3000 Kgms-1

Final momentum of the system = (300 × 4.12) + (125 × x) = (1236 + 125x) Kgms-1

Using the principle of conservation of linear momentum;

Total momentum before collision = Total momentum after collision

m1u1 + m2u2 = m2v1 + m2v2

(300 × 10) + (125 × 0) = (300 × 4.12) + (125 × x)

3000 = 1236 + 125x

x =  3000 -  1236 /125

x = 14 ms-1

The speed with which Melinda’s car is bumped across the floor is 14 ms-1.

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explain how the spray painting process makes use of static electricity

Answers

Answer:

The spray paint gun is charged positively, which causes every paint particle to become positively charged. Since the paint particles all have the same charge, they repel each other and produce a fine mist of paint which is sprayed towards the wall/car.

Answer:

xerography can i get brainliest

Explanation:

Calculate the Work done if the force is 2000 Newtons
and the distance is 5 km.

Answers

Answer:

10 million joules or 10,000 KJ

Explanation:

Work= Force x Displacement

convert 5km into meters -5km=5000m

W= 2000N x 5000m

w=10,000,000 Joules

or 10,000KJ

PLZZZ HELPPP ASAP
I really need help as soon as possible

Answers

Answer:

Friction

Explanation:

As the toy cars rolls away, more friction is created. The more friction there is, the more friction on surface rubs against another which creates friction which in-term slows it down. Hope this helps.

Which of these ALL require direction? Force, Time, Acceleration Displacement, Velocity, Force Mass, Time, Speed Speed, Velocity, Distance



PLS ANSWER QUICK!!!!

Answers

Answer:

force, acceleration, displacement, velocity requires direction

13. What are some ways that you can conserve energy?

Answers

Answer:

Adjust your day-to-day behaviors.

Replace your light bulbs.

Use smart power strips.

Install a programmable thermostat.

Use energy efficient appliances.

Reduce water heating expenses.

Install energy efficient windows.

Upgrade your HVAC system.

Turn Off Lights and Electronics When You Aren't Using Them. ...

Replace Traditional Light Bulbs with LEDs. ...

Get a Smart Thermostat. ...

Ensure Your Home is Properly Insulated. ...

Put Decorative Lights on a Timer. ...

Identify and Unplug Energy Vampires. ...

Reduce Appliance Use. ...

Use Less Hot Water.

Shown below is a parallel circuit of two light bulbs.
(
Bulb 1
Bulb 2
Which statement best describes what will most likely happen if Bulb 1 burns out?
A. Bulb 2 will also burn out.
B. Bulb 2 will blink off and on.
C. Bulb 2 will stay lit, but will be a dimmer light source.
D. Bulb 2 will stay lit and the light source will be stronger.
NG

Answers

The characteristics of parallel circuits allow to find the correct answer for the question about what happens when a light bulb is:  

   D) Bulb 2 will stay lit and the light source will be stronger.

Electrical circuits have two forms and connection:  

   • Serie. In this case there is only one path through which current can circulate the current.  

   • Parallel. There are several roads where the current can circulate.  

In a parallel circuit, the total current in the circuit is the sum of the current in each branch, the voltage in all branches remains constant.

Let's analyze the claims:  

A) False. The bulbs are independent, what happens to one does not affect the other.

B) False. Both bulbs were on, so the second bulb should not be affected.  

C) False. When burn a light bulb, there is more current in the other branch, The opposite happens.  

D) True. When burn a light bulb there is more current in the other branch and therefore the light bulb 2 can dissipate more power by shining a little brighter.

In conclusion, using the characteristics of parallel circuits we can find that the correct answer for the question about what happens when a light bulb burns out is:  

        D) Bulb 2 will stay lit and the light source will be stronger.

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The gravitational force on Mars is about 38% of Earth. What would a cat weighing 15 pounds on Earth weigh on Mars?

Answers

Answer: 5.7

Explanation: 38% of 15.

The weight we experience ourselves and the ability to stand in the ground is due to the gravitational pull of earth. If this pull is lower we feel weight loss. So the cat will have a weight of 5.7 pounds or 2.58 kg in mars where the gravitation is about 38% of earth.

What is gravitational force?

Gravitational force is a kind force by which a body attracts other objects into its centre of mass. Earth have strong gravitational effect on objects and thus we are all standing on the surface and everything falling from a height hits the ground.

As the mass of the object increases, gravitational effect also increases. The weight experienced by a body is the product of its mass and gravity. Thus massive body have greater weight.

Our mass is constant everywhere but weight will change according a change in gravity. Mars  have only 38% of gravity of earth. Thus the cat weighing 15 pounds on earth will loss its weight in mars by 38%.

Thus, 15 × 38/100= 5.7 pounds will be the weight of the cat in mars.

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Choose all the answers that apply.

Light _____.
A. cannot travel through a vacuum
B. slows down when traveling through denser substances
C. speeds up when traveling through more dense substances
D. travels in transverse waves
E. can be absorbed and transformed into heat

Answers

Answer:

B

Explanation:

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