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ankoles [38]
4 years ago
12

Reviewing old tests and quizzes will not help you determine what will be on a test because teachers don’t like to give students

hints about what could be on future tests. Please select the best answer from the choices provided T or F
Physics
2 answers:
kifflom [539]4 years ago
5 0

Answer:

False

Explanation:

riadik2000 [5.3K]4 years ago
4 0

Answer:

It is false

Explanation:

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In one hour, coal supplies 500 000 J of energy. The energy amounts to 380 000 J. How much useful energy is produced in one hour?
Debora [2.8K]

Answer:

120,000J

Corrected question;

In one hour, coal supplies 500 000 J of energy. The wasted energy amounts to 380 000 J. How much useful energy is produced in one hour?

Explanation:

Given;

Total energy Et = 500,000 J

Wasted Energy Ew = 380,000J

The amount useful energy is the amount of energy that is available for supply.

This can be derived by subtracting the wasted energy from the total energy.

Useful energy = Total Energy - wasted energy

Eu = Et - Ew

Substituting the given values;

Eu = 500,000J - 380,000

Eu = 120,000 J

The amount of useful energy produced in one hour is 120,000 J

5 0
3 years ago
An oceanic depth-sounding vessel surveys the
IgorC [24]
So you would divide 1530 by 8 and that’s how you’d get your answer, so it should be (blank)m
3 0
3 years ago
4.00 kg glass coffee cup is 30.0°C at room temperature. It is then plunged into hot dishwater at a temperature of 90.0°C, as sho
statuscvo [17]

Answer:

Q = 200800 Joules.

Explanation:

Given the following data;

Mass = 4kg

Initial temperature = 30.0°C

Final temperature = 90.0°C

Specific heat capacity of glass = 837 J/kg°C

To find the quantity of heat absorbed;

Heat capacity is given by the formula;

Q = mcdt

Where;

Q represents the heat capacity or quantity of heat.

m represents the mass of an object.

c represents the specific heat capacity of water.

dt represents the change in temperature.

dt = T2 - T1

dt = 90 - 30

dt = 60°C

Substituting the values into the equation, we have;

Q = 4*837*60

Q = 200800 Joules.

Therefore, the amount of heat absorbed is 200800 Joules.

8 0
3 years ago
Helium-oxygen mixtures are used by divers to avoid the bends and are used in medicine to treat some respiratory ailments. What p
Temka [501]

Answer:

The percentage by mole of Helium present in the Helium-Oxygen mixture is = 66.6%

Explanation:

From General gas equation.

PV = nRT...............................  Equation 1

Where n = number of moles, V = volume, P = pressure, T = temperature, P = pressure, V = volume.

n = mass/molar mass .................. Equation 2

substituting equation 2 into equation 1.

PV = (mass/molar mass)RT

⇒ Mass/molar mass = PV/RT..................... Equation 3

But mass = Density × Volume

⇒ M = D × V.................... Equation 4

Where D = density, M = mass

Substituting equation 4 into equation 3

DV/molar mass = PV/RT............ Equation 5

Dividing both side of the equation by Volume (V) in Equation 5

D/molar mass = P/RT .............. Equation 6

Cross multiplying equation 6

D × RT = P × molar mass

∴ Molar mass = (D × RT)/P.................. Equation 7

Where D = 0.518 g/L , R = 0.0821 atm dm³/K.mol,

T = 25°C = 25 + 273 = 298 K,

P =721 mmHg = (721/760) atm= 0.949 atm

Substituting these values into equation 7

Molar mass = (0.518 × 0.0821 × 298)/0.949

Molar mass = 13.35 g/mole

The molar mass of the mixture is =13.35 g/mole

Let y be the mole fraction of Helium and 1-y be the mole fraction of oxygen.

∴ 13.35 = 4(y) + 32(1-y)

13.35 = 4y + 32 - 32y

Collecting like terms in the equation,

32y - 4y = 32 - 13.35

28y = 18.65

y = 18.65/28

y =0.666

y = 0.666 × 100 = 66.6%

∴The percentage by mole of Helium present in the Helium-Oxygen mixture is = 66.6%

6 0
3 years ago
Which defintion of heat is most scientifically accurate
lukranit [14]
Hi there

Definition of heat

the quality of being hot; high temperature.
6 0
3 years ago
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