Ask question

Ask question

All categories

3 years ago

7

A car engine burns gas at 495 K, and exhausts to the air at 293 K. If it ran at the highest possible efficiency, how much input

heat would it take to do 10,000 J of work? (Unit=J)

1 answer:

slamgirl [31]3 years ago

4 0

The heat taken to do the 10,000 J of work is 4081 J

<u>Explanation:</u>

The ratio of the temperature difference between the reservoirs and the temperature of the hot reservoir is termed as maximum thermal efficiency.

Maximum thermal efficiency is

1 - (Tc / Th).

where Tc represents the absolute temperature of the cold reservoir

Th represents the absolute temperature of the hot reservoir.

1 - (293/495) = 0.408

If the input is 10,000 J, then 4081 J is used to do work. The remaining 5919 J is rejected as heat into the air.

You might be interested in

How much force is needed to accelerate a 20 kg mass at a rate of 4 m/s to the second power?

dusya [7]

Answer:

So 55 Newtons are needed.

6 0

2 years ago

Read 2 more answers

In a college homecoming competition, eighteen students lift a sports car. While holding the car off the ground, each student exe

Nata [24]

Answer:

Explanation:

Given

Each student exert a force of $F=400 N$

Let mass of car be m

there are 18 students who lifts the car

Total force by 18 students $F=18\times 400=7200 N$

therefore weight of car $W=7200$

mass of car $m=\frac{W}{g}$

$m=\frac{7200}{9.8}=734.69 kg$

(b) $7200 N \approx 1618.624\ Pound-force$

$734.69 kg\approx 1619.71 Pounds$

6 0

2 years ago

A ball rolls of buildings that is 100m high calculate the time that it takes for ball to hit the ground

LUCKY_DIMON [66]

Answer:

2as=v2-u2

2000=v2

V=44

V=u+at

44/10=t

T=4.4seconds

5 0

3 years ago

Loudspeakers can produce intense sounds with surprisingly small energy input in spite of their low efficiencies. Calculate the p

Dennis_Churaev [7]

Answer:

$5.87*10^{-4}W$

Explanation:

Given that:

$\beta = 89,6 dB$

$D = 13.0 cm$

$r = \frac{D}{2}\\ = \frac{13.0}{2}\\ = 6.5 cm\\=0.065m$

Efficiency = 2.06 % = 0.0206

The intensity level of sound is given by the formula:

$\beta = (10dB) log (\frac{I}{I_o} )$

$\frac{\beta}{(10dB) } =log (\frac{I}{I_o} )$

Taking their exponential; we have :

$10^{\frac{\beta}{10dB}}= \frac{I}{I_o}$

$I = I_o(10^{\frac{\beta}{10dB}})$

Replacing our values; we have:

$I = (10^{-12}W/m^2)(10^{\frac{89.6}{10dB}})$

$= 9.12 *10^{-4}W/m^2$

Power Output;

$P_{out} = IA\\P_{out}=I(\pi r^2)\\P_{out}=(9.12*10^{-4}W/m^2)(3.14)(0.065m)^2\\P_{out}=1.2099048*10^{-5} W$

The power output that is required to produce a 89.6 dB sound intensity level for a 13.0 cm diameter speaker that has an efficiency of 2.06% is;

$P_{in}= \frac{P_{out}}{0.0206}$

$P_{in}= \frac{{1.2099048*10^{-5}}}{0.0206}$

$P_{in}= 5.87*10^{-4}W$

Therefore, The power output that is required to produce a 89.6 dB sound intensity level for a 13.0 cm diameter speaker that has an efficiency of 2.06% is $5.87*10^{-4}W$

8 0

3 years ago

Which of the following is a feature of the sun's radiation?

Firdavs [7]

The sun's radiation is made up of rays of many different wavelengths.

8 0

2 years ago

Read 2 more answers