Physics : asked on lorettawintx

22.11.2022

An immersion heater has a thermostat to control the water temperature in a hot water tank. When the temperature of the water inside the tank reaches 58°C the thermostat switches the heater off. The thermostat switches the heater back on when the temperature of the water falls to 50°C. The graph shows how the temperature of the water inside a hot water tank changes with time. The tank is not insulated. Which of the following gives the best explanation why the temperature of the water falls at the fastest rate just after the heater switches off?

Step-by-step answer

13.02.2022, solved by verified expert

Ranjana Bhatt

p PhD

Chemistry, Q&A Expert

17 461

29 102 answers

5 rating

Unlock the full answer

Here, Ambient temperature or temperature of surrounding is not given but as the liquid temperature drop so we can say the ambient temperature is less than 50°C . Method of heat transfer is convection.

Newton's law of cooling states that the rate at which an object cools is proportional to the difference in temperature between the object and the object's surroundings.

The difference of between the temperatures is maximum when the heater just switched off. So according to Newton's law of cooling the temperature of the water falls at the fastest rate just after the heater switches off.

It is was helpful?

Helpful Useless

Faq

Physics

Bees can see into the ultraviolet region of the electromagnetic spectrum. Compared with humans, bees can sense electromagnetic waves that have a lower frequency and a shorter wavelength. a higher frequency and a longer wavelength. a lower frequency and a longer wavelength. a higher frequency and a shorter wavelength.

Step-by-step answer

P Answered by Specialist

Options:
a. a lower frequency and a shorter wavelength.
b. a higher frequency and a longer wavelength.
c. a lower frequency and a longer wavelength.
d. a higher frequency and a shorter wavelength

Answer:
d. a higher frequency and a shorter wavelength

Explanation:
The frequency of a wave is inversely proportional to its wavelength. That means that waves with a high frequency have a short wavelength, while waves with a low frequency have a longer wavelength. Light waves have very, very short wavelengths.
For example, Gamma rays have the highest energies, the shortest wavelengths, and the highest frequencies. Radio waves, on the other hand, have the lowest energies, longest wavelengths, and lowest frequencies of any type of EM radiation.
Options:
a. a lower frequency and a shorter wavelength.
b. a higher frequency and a longer wavelen

Physics

An amateur player is about to throw a dart with an initial velocity of 15 meters/second onto a dartboard that is at a distance of 2.7 meters. Calculate the vertical distance by which the player will miss the target if he throws the dart horizontally, in line with the dartboard.

Step-by-step answer

P Answered by Specialist

Options:
a. 0.08 meters
b. 0.16 meters
c. 0.32 meters
d. 1.8 meters

Answer:
b. 0.16 meters

Explanation:
In the picture
Options:
a. 0.08 meters
b. 0.16 meters
c. 0.32 meters
d. 1.8 meters

Answer:
b. 0.16 meters

Physics

The system shown above consists of two identical blocks that are suspended using four cords, each of a different length. Which of the following claims are true about the magnitudes of the tensions in the cords?

Step-by-step answer

P Answered by Specialist

Answer: Option B and C are True.

Explanation:
The weight of the two blocks acts downwards.
Let the weight of the two blocks be W. Solving for T₁ and T₂:
w = T₁/cos 60° -----(1);
w = T₂/cos 30° ----(2);
equating (1) and (2)
T₁/cos 60° = T₂/cos 30°;
T₁ cos 30° = T₂ cos 60°;
T₂/T₁ = cos 30°/cos 60°;
T₂/T₁ =1.73.
Therefore, option a is false since T₂ > T₁.
Option B is true since T₁ cos 30° = T₂ cos 60°.
Option C is true because the T₃ is due to the weight of the two blocks while T₄ is only due to one block.
Option D is wrong because T₁ + T₂ > T₃ by simple summation of the two forces, except by vector addition.
Answer: Option B and C are True.

Explanation:
The weight of the two blocks acts downwards.
Le

Physics

Abbey always gets zits on her chin and she can t figure out the best method to get rid of them. She decides to test several products to see which clears her face up fastest: washing with soap and water, washing with an acne face wash from the pharmacy, and washing her face with organic oils. For one week she just washes her face with water. The next week she washes every day with soap and water. The following week she uses the acne wash, and the last week she uses the organic oils. Each week she records the number of zits she has on her chin at

Step-by-step answer

P Answered by PhD

Independent variable: the best method to get rid of them.

Dependent variable: washing with soap and water.

Hypothesis: Organic oils

Control group: water

Physics

Sandra has five cubes each made of a different metal. Each cube has a mass of 100 grams. Which procedure should Sandra use to best determine which metal cube transfers to most heat to 500 grams of water? A. Heat each cube to a the same temperature, place each cube into different containers with 500 grams of water at different temperatures, and measure the temperature of the water. B. Heat each cube to a different temperature, place each cube into different containers with 500 grams of water at the same temperature, and measure the temperature of

Step-by-step answer

P Answered by PhD

Answer:

Option D

Step-by-step explanation:

D.
Heat each cube to the same temperature, place each cube into different containers with 500 grams of water at the same temperature, and measure the temperature of the water.

Physics

A proton (1.6726 ? 10-27 kg) and a neutron (1.6749 ? 10-27 kg) at rest combine to form a deuteron, the nucleus of deuterium or “heavy hydrogen.” In this process, a gamma ray (high-energy photon) is emitted, and its energy is measured to be 2.2 MeV (2.2 ? 10 6 eV).

Step-by-step answer

P Answered by Master

Answer:

see below.

Step-by-step explanation:

To solve this problem, we can use the conservation of energy and conservation of momentum principles.

Conservation of energy:

The total initial energy is the rest energy of the proton and neutron, which is given by:

Ei = (mp + mn)c^2

where mp and mn are the masses of the proton and neutron, respectively, and c is the speed of light.

The total final energy is the rest energy of the deuteron plus the energy of the gamma ray, which is given by:

Ef = (md)c^2 + Eg

where md is the mass of the deuteron and Eg is the energy of the gamma ray.

According to the conservation of energy principle, the initial energy and final energy must be equal, so we have:

Ei = Ef

(mp + mn)c^2 = (md)c^2 + Eg

Conservation of momentum:

The total initial momentum is zero because the proton and neutron are at rest. The total final momentum is the momentum of the deuteron and the momentum of the gamma ray. Since the gamma ray is massless, its momentum is given by:

pg = Eg/c

where pg is the momentum of the gamma ray.

According to the conservation of momentum principle, the total final momentum must be equal to zero, so we have:

0 = pd + pg

where pd is the momentum of the deuteron.

Solving for md and pd:

From the conservation of energy equation, we can solve for md:

md = (mp + mn - Eg/c^2)/c^2

Substituting this expression into the conservation of momentum equation, we get:

pd = -pg = -Eg/c

Substituting the given values, we have:

mp = 1.6726 × 10^-27 kg mn = 1.6749 × 10^-27 kg Eg = 2.2 × 10^6 eV = 3.52 × 10^-13 J

Using c = 2.998 × 10^8 m/s, we get:

md = (1.6726 × 10^-27 kg + 1.6749 × 10^-27 kg - 3.52 × 10^-13 J/(2.998 × 10^8 m/s)^2)/(2.998 × 10^8 m/s)^2 = 3.3435 × 10^-27 kg

pd = -Eg/c = -(3.52 × 10^-13 J)/(2.998 × 10^8 m/s) = -1.1723 × 10^-21 kg·m/s

Therefore, the mass of the deuteron is 3.3435 × 10^-27 kg, and its momentum is -1.1723 × 10^-21 kg·m/s.

Physics

A puck moves 2.35 m/s in a -22.0° direction. A hockey stick pushes it for 0.215 s, changing its velocity to 6.42 m/s in a 50.0° direction. What was the magnitude of the acceleration?

Step-by-step answer

P Answered by PhD

Answer:
7.25 secs.

Explanation:
First find the distance it takes to stop
s = [v^2-u^2]/2a = 0^2 - 8.7^2/2[-2.4] = 8.7^2/4.8
Next find the time it takes to go that distance , s = ut +[1/2] at^2
8.7^2/4.8 = 8.7t +[1/2] [ -2.4]t^2 , rearrange and
t^2 -[8.7/1.2]+ 8.7^2/[(1.2)(4.8)]=0 complete the square
[t - (8.7/2.4)]^2=0
t = 8.7/2.4 = 3.625 secs
At this stage the deceleration will push the object back in the direction it came from for another 3.625 secs when it will be 8.7 m/s again
Total time , T =2t = 7.25 secs.

Note:
The term differential is used in calculus to refer to an infinitesimal (infinitely small) change in some varying quantity. For example, if x is a variable, then a change in the value of x is often denoted Δx (pronounced delta x). The differential dx represents an infinitely small change in the variable x.

Physics

compare the momentum of a 6,300 kg elephant walking 0.11 m/s and a 50-kg dolphins swimming 10.m/s

Step-by-step answer

P Answered by PhD

First sum applied the Newton's second law motion: F = ma
Force = mass* acceleration
This motion define force as the product of mass times Acceleration (vs.Velocity). Since acceleration is the change in velocity divided by time,
force=(mass*velocity)/time
such that, (mass*velocity)/time=momentum/time
Therefore we get mass*velocity=momentum
Momentum=mass*velocity
Elephant mass=6300 kg; velocity=0.11 m/s
Momentum=6300*0.11
P=693 kg (m/s)
Dolphin mass=50 kg; velocity=10.4 m/s
Momentum=50*10.4
P=520 kg (m/s)
The elephant has more momentum(P) because it is large.

Physics

An electrical kettle supplies 20,000j of energy to heat 0.5kg of water. What is the temperature change? The specific heat capacity of water is 4200j/kg.

Step-by-step answer

P Answered by PhD

The change in temperature is 9.52°CExplanation:Since, the heat supplied by the electric kettle is totally used to increase the temperature of the water.Thus, from the law of conservation of energy can be stated as:Heat Supplied by Electric Kettle = Heat Absorbed by WaterHeat Supplied by Electric Kettle = m C ΔTwhere,Heat Supplied by Electric Kettle = 20,000 JMass of water = m = 0.5 kgSpecific Heat Capacity of Water = C = 4200 J/kg.°CChange in Temperature of Water = ΔTTherefore,20,000 J = (0.5 kg)(4200 J/kg.°C) ΔTΔT = 20,000 J/(2100 J/°C)ΔT = 9.52°C

Physics

Jordan lifts a 100-kilogram barbell from the floor to a height of 2.0 meters in 1.5 seconds. The amount of power he generates is about ____ watts.

Step-by-step answer

P Answered by PhD

Weight of barbell (m) = 100 kg
Uplifted to height (h) = 2m
Time taken= 1.5 s
Work done by Jordan = potential energy stored in barbell = mgh
= 100×2×9.8
= 1960J
Power = energy/time
= 1960/1.5
1306.67watts

free Ask question

Today we have helped

2 815 students

just now

Physics

You are driving up a long, inclined road. After 1.50mi you notice that signs along the roadside indicate that your elevation has increased by 510ft . b) How far do you have to drive to gain an additional 110ft of elevation

p Answered by PhD

just now

English

Read the excerpts from "opening statements from John F. Kennedy and Richard M. Nixon First Televised Debate." Kennedy: This is a great country, but I think it could be a greater country; and this is a powerful country, but I think it could be a more powerful country. I'm not satisfied to have fifty percent of our steel-mill capacity unused. I'm not satisfied when the United States had last year the lowest rate of economic growth of any major industrialized society in the world.

Nixon: Let's put it in terms that all of us can understand. We often hear gross national product discussed and in that respect may I say that when we compare the growth in this Administration with that of the previous Administration that then there was a total growth of eleven percent over seven years; in this Administration there has been a total growth of nineteen per cent over seven years. That shows that there's been more growth in this Administration than in its predecessor.

Which best analyzes a difference in the evidence used by each speaker to reach his conclusion?

Kennedy uses facts to compare U.S. economic growth with other industrialized nations, which show the U.S. is lagging; Nixon uses facts to compare the economic growth during this presidency to that during the previous one, which shows that the economy is improving.

Kennedy makes a common assertion about how he will improve the U.S. steel industry; Nixon uses facts to demonstrate that the steel industry, while not perfect, has come a long way in the past seven years.

Kennedy uses specific statistics to argue that economic growth in the U.S. is lagging behind other nations; Nixon relies on common assertions and opinions, rather than facts, to show that the U.S.'s economic growth is forging ahead.

Kennedy compares U.S. steel production to that of other countries to show that the U.S. is lagging; Nixon compares steel production now to steel production during the Truman presidency to show that it is forging ahead.

p Answered by PhD

1 minute ago