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14.01.2023

A 1800 kg hybrid vehicle operates on ethanol and is equipped with a multipurpose motorgenerator-flywheel. When the vehicle slows or stops, 50% of the kinetic energy is recovered as electrical energy in the battery. When the IC engine is used to recharge the battery, there is a 25% efficiency of converting chemical energy in the fuel to electrical energy stored in the battery. The vehicle slows from 70 miles per hour to 20 miles per hour. Calculate:

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24.06.2023, solved by verified expert

Bhaskar Singh Bora

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This question is incomplete, the complete question is;

A 1800 kg hybrid vehicle operates on ethanol and is equipped with a multipurpose motorgenerator-flywheel. When the vehicle slows or stops, 50% of the kinetic energy is recovered as electrical energy in the battery. When the IC engine is used to recharge the battery, there is a 25% efficiency of converting chemical energy in the fuel to electrical energy stored in the battery. The vehicle slows from 70 miles per hour to 20 miles per hour. Calculate: (A) Electrical energy recovered in the battery in [kJ] (B) Mass of fuel needed to store same amount of energy in the battery in [kg]

a) Electrical energy recovered in the battery is 404.6895 kJ

b) Mass of fuel needed to store same amount of energy in the battery is 0.0606 kg

Explanation:

Given that;

Initial speed of the vehicle V = 70 miles per hour = 31.293 m/s

Final speed of the vehicle u = 20 miles per hour = 8.941 m/s

mass of vehicle m = 1800 kg

Noe, change in kinetic energy of the vehicle will be;

= m( v² - u² )

we substitute

= × 1800( (31.293)² - (8.941)² )

= 900( 979.2518 - 79.9414)

= 900 × 899.3104

= 809379.36 J

= 809.379 kJ

now, Electrical energy recovered in the battery when the vehicle slows will be;

= 50% ×

= 50/100 × 809.379 kJ

= 404.6895 kJ

Therefore, Electrical energy recovered in the battery is 404.6895 kJ

For this electrical energy to be obtained from fuel, the chemical energy required will be;

= / 25%

= 404.6895 kJ / 0.25

= 1618.758 kJ

Heat energy released per mass of ethanol combustion

(Lower heating value of ethanol) is 26.7kJ/g

Now, the mass of fuel needed to generate 1618.758 kJ will be;

= 1618.758 kJ / 26.7kJ/g

= 60.63 g

= 0.0606 kg

Therefore, Mass of fuel needed to store same amount of energy in the battery is 0.0606 kg

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Physics

Step-by-step answer

P Answered by PhD

This question is incomplete, the complete question is;

a) Electrical energy recovered in the battery is 404.6895 kJ

b) Mass of fuel needed to store same amount of energy in the battery is 0.0606 kg

Explanation:

Given that;

Initial speed of the vehicle V = 70 miles per hour = 31.293 m/s

Final speed of the vehicle u = 20 miles per hour = 8.941 m/s

mass of vehicle m = 1800 kg

Noe, change in kinetic energy of the vehicle will be;

$E_{kinetic}$ = $\frac{1}{2}$ m( v² - u² )

we substitute

= $\frac{1}{2}$ × 1800( (31.293)² - (8.941)² )

= 900( 979.2518 - 79.9414)

= 900 × 899.3104

= 809379.36 J

$E_{kinetic}$ = 809.379 kJ

now, Electrical energy recovered in the battery when the vehicle slows will be;

$E_{battery}$ = 50% × $E_{kinetic}$

$E_{battery}$ = 50/100 × 809.379 kJ

$E_{battery}$ = 404.6895 kJ

Therefore, Electrical energy recovered in the battery is 404.6895 kJ

For this electrical energy to be obtained from fuel, the chemical energy required will be;

$E_{chemical}$ = $E_{battery}$ / 25%

$E_{chemical}$ = 404.6895 kJ / 0.25

$E_{chemical}$ = 1618.758 kJ

Heat energy released per mass of ethanol combustion

(Lower heating value of ethanol) is 26.7kJ/g

Now, the mass of fuel needed to generate 1618.758 kJ will be;

$m_{fuel}$ = 1618.758 kJ / 26.7kJ/g

$m_{fuel}$ = 60.63 g

$m_{fuel}$ = 0.0606 kg

Therefore, Mass of fuel needed to store same amount of energy in the battery is 0.0606 kg

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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.
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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.
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Explanation:
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Step-by-step answer

P Answered by PhD

Answer:
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Explanation:
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Next find the time it takes to go that distance , s = ut +[1/2] at^2
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Note:
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Step-by-step answer

P Answered by PhD

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P Answered by PhD

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Step-by-step answer

P Answered by PhD

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Step-by-step answer

P Answered by PhD

Weight of jasmine (m) = 400 N
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P Answered by PhD

The horizontal and vertical motions of balloons are independent from each other.
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Step-by-step answer

P Answered by PhD

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