*define convection

*list three examples in the world around you where convection currents are important. Give a short description of each.

Water heater

In a water heater, tap water with the temperature 10 degrees celcius is heated to 60 degrees celcius. For a shower, a total of 20 litres of water is used. Water from the water heater is mixed with tap water to reach the temperature 35 degrees celcius when one showers.

1. How much ENERGY is needed to heat 10 litres of water from 10 celcius to 60 celcius?

2. How much EXERGY is needed to heat 10 litres of water from 10 celcius to 60 celcius?

3. How much ENERGY is needed to heat 20 litres of water from 10 celcius to 35 celcius?

4. How much EXERGY is needed to heat 20 litres of water from 10 celcius to 35 celcius?

5. What is the change in entropy when 10 litres of water with the temperature 10 celcius is mixed with 10 litres of water with the temperature 60 celcius?

what is eddy current.explain minimum in 100 words.

All of the following is an example of random error except

Group of answer choices

Poor thermal contact between thermometer and object being measured.

Vibrations in air current when measuring mass

Inconsistent environmental temparature

Irregularities in the object being measured

When all measurements of a quantity are consistently bigger or consistently smaller than the true value, these best indicates ________________________

Group of answer choices

Systematic error in measurements

Normal variation

All of the above

Random error in measurements

A t score value of zero implies

Group of answer choices

The measured and actual value are the same (a perfect result)

The discrepancy is one standard deviation

The measured value is largely deviated from the actual value and unacceptable

No correlation between measured value and actual value

For a picket fence in free-fall, the measured time between every displacement (△ x) will __________. (Hint: Velocity gradually increases from initial velocity value)

Group of answer choices

Remain constant

Decrease

Increase

Oscillate

Michael Jordan is riding the Giant Drop at Great America. If Michael Jordan falls for 2600 milliseconds, what will be his final velocity and how far will he fall?

Type in your correct answers and have the correct units by them for full points

Use g = 9.8 m s − 2

You are working with a team designing capacitors for specialized purposes. One client needs a capacitor shaped like a sphere that can store the most energy for its size. You are to begin the design process by performing calculations for a simple spherical capacitor consisting of two thin concentric spherical shells separated by a dielectric. You decide to calculate the maximum energy that can be stored in terms of the radius of the outer shell and the maximum electric field that the dielectric can withstand before breaking down.

After you have derived a symbolic answer, get an idea of how much energy this is by finding a numerical answer for a capacitor with an outer shell that has a radius of 5 cm (about the size of a softball), filled with a dielectric with a breakdown voltage of 150 x 10⁶ V/m and a dielectric constant of 3.

(a)  Give a purely symbolic answer to the problem in terms of (only) the quantities given in the problem and known constants. Be sure to define each of the symbols you use.

(b) Give a numerical answer to the problem.

Enter the data from the table below into Microsoft Excel and determine the linear correlation coefficient, R2 for time versus position.
Then, calculate y/t and determine the linear correlation coefficient, R2 for time versus y/t. Write in the calculated values in the table below (use two decimal places).

1. Determine the linear correlation coefficients, R2, for both the y vs. t data and the y/t vs. t data. (Both to four decimal places.)

   For y vs. t, R2 = ____________ For y/t vs. t, R2 = ____________

2. Using the linearized relationship, y/t vs. t, report the properly rounded best estimate for ?. (?"## = 980.35 ??/?0.)

g =

%diff=

Part b.
A thin hoop of mass 22 kg and radius 1.5 m rolls down an incline that is 4 meters tall. What is the velocity of the thin hoop at the bottom of the incline?

m/s



Part c.
A solid disk of mass 22 kg and radius 1.5 m rolls down an incline that is 4 meters tall. What is the velocity of the solid disk at the bottom of the incline?

m/s

5.

[–/1 Points]DETAILSMY NOTES

A 10.3 kg tire that has a moment of inertia of 2340 kgm^2 is initially turning at 20.5 revolutions/s. It coasts to rest after 131 revolutions. What is the magnitude of the torque that slowed it?

N-m

6.

[–/1 Points]DETAILSMY NOTES

With her arms held against her body, a figure skater has a moment of inertia of 0.65 kg-m^2. With her arms extended, her rotational speed is 0.21 rev/s. But when she draws in her arms, her rotational speed is 0.74 rev/s. What is her moment of inertia when her arms are extended?

kg-m^2

Make an essay of 2-3 paragraphs and discuss the nature of an exponentially growing quantity. Describe its characteristics. Discuss population growth as an example. Discuss the impact of population growth on the demand for electric power in the U.S. Explain why electric power use can grow faster than population growth. What impact does this have on quality of life issues, both for the general public, and those in the energy industries? What’s the impact on energy resource, and disposal of waste products such as greenhouse gasses and nuclear waste?

(a)

In reaching equilibrium, how much heat transfer (in J) occurs from 1.00 kg of water at 40.5°C when it is placed in contact with 1.00 kg of 23.0°C water?

J

(b)

What is the change in entropy (in J/K) due to this heat transfer?

J/K

(c)

How much work is made unavailable (in J), taking the lowest temperature to be 23.0°C?

J

Explicitly show how you follow the steps in the Problem-Solving Strategies for Entropy. (Submit a file with a maximum size of 1 MB.)

An object on a single oscillating string may be modelled by differential equation x"(t)=-x(t)
x(t) is the signed length of the string at time t.

a) the trivial solution x(t) =0 satisfies the differential equation. describe what physical scenario this solution represents.
b) find at least three other solutions to the differential equation
c) describe what it means for this differential equation to have multiple solutions. what do the solutions represent.
d) suppose a string is damped by friction. propose and justify a amendment to the differential equation that accounts for the damping force.

A small bullet of mass m=0.24kg and speed v=17.8m/s embeds in a block of mass M=0.75kg suspended by a massless string of length L, after a collision as shown in the figure. If the bullet will appear on the other side of the block M with a speed v'=5m/s, instead of being embedded in it, find the maximum height the block M can reach. (Take g=9.81 m/s²). Express your answer using two decimal places.

An electron in a television picture tube travels at 3 × 107 m/s. Does the earth’s gravitational field or its magnetic
field exert the greater force on the electron? Assume v is perpendicular to B.

Three people pull simultaneously on a stubborn donkey. Jack pulls eastward with a force of 76.9 N, Jill pulls with 70.9 N in the northeast direction, and Jane pulls to the southeast with 163 N. (Since the donkey is involved with such uncoordinated people, who can blame it for being stubborn?) Find the magnitude of the net force the people exert on the donkey.