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podryga [215]
3 years ago
12

In one cycle, a heat engine takes in 1000 J of heat from a high-temperature reservoir, releases 600 J of heat to a lower-tempera

ture reservoir, and does 400 J of work. What is its efficiency?
Physics
1 answer:
Talja [164]3 years ago
4 0

Answer:

η = 40 %  

Explanation:

Given that

Qa ,Heat addition= 1000  J

Qr,Heat rejection= 600 J

Work done ,W= 400 J

We know that ,efficiency of a engine given as

\eta=\dfrac{W(net)}{Q(heat\ addition)}

Now by putting the values in the above equation ,then we get

\eta=\dfrac{400}{1000}

η = 0.4

The efficiency in percentage is given as

η = 0.4  x 100 %

η = 40 %

Therefore the answer will be 40%.

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3. A model rocket takes 0.05 seconds to speed up from rest to its maximum velocity of 80 m/s.
nikklg [1K]

Answer:

1600 \frac{m}{s^2}

Explanation:

Acceleration is defined as the change in velocity divided by the time it took to produce such change. The formula then reads:

a = \frac{change-in-velocity}{time} = \frac{Vf-Vi}{t}

Where Vf is the final velocity of the object, (in our case 80 m/s)

Vi is the initial velocity of the object (in our case 0 m/s because the object was at rest)

and t is the time it took to change from the Vi to the Vf (in our case 0.05 seconds.

Therefore we have:

a = \frac{80 m/s - 0 m/s}{0.05 sec} = 1600 \frac{m}{s^2}

Notice that the units of acceleration in the SI system are \frac{m}{s^2} (meters divided square seconds)

7 0
3 years ago
Read 2 more answers
6. What are 3 different evidences of evolution? How is each form used to provide evidence of evolution?
Cloud [144]

Answer:

Divergent - This type of evolution often occurs when closely related species diversify to new habitats. On a large scale, divergent evolution is responsible for the creation of the current diversity of life on earth from the first living cells. On a smaller scale, it is responsible for the evolution of humans and apes from a common primate ancestor.

Convergent - Convergent evolution causes difficulties in fields of study such as comparative anatomy. Convergent evolution takes place when species of different ancestry begin to share analogous traits because of a shared environment or other selection pressure. For example, whales and fish have some similar characteristics since both had to evolve methods of moving through the same medium: water.

Parallel evolution - Parallel evolution occurs when two species evolve independently of each other, maintaining the same level of similarity. Parallel evolution usually occurs between unrelated species that do not occupy the same or similar niches in a given habitat.

6 0
3 years ago
What is the source of all electromagnetic waves?
kherson [118]

Answer:

Accelerating charges.

Explanation:

Electromagnetic waves are waves produced by the vibration of both electrical and magnetic fields.

This interaction produces an energy source that does not require any medium to propagate.

To produce electromagnetic waves, electric and magnetic fields must be vibrating.

An electric charge produced when vibrating under voltage will produce electromagnetic waves. This is the same for all sources of these waves.

The sun produces electromagnetic waves. A lot of human activities also does this.

6 0
3 years ago
A ball is kicked at an angle of 35 degrees with the ground. What should be the initial velocity of the ball so that it hits a ta
pashok25 [27]

Answer:

18.5 M/S

Explanation:

trust me

6 0
3 years ago
rickey approaches third base. He dives head first, hitting the ground at 6.75 m/s and reaching the base at 5.91 m/s in 2.5 secon
Gekata [30.6K]

Answer:

15.825 m

Explanation:

t = Time taken = 2.5 s

u = Initial velocity = 6.75 m/s

v = Final velocity = 5.91 m/s

s = Displacement

a = Acceleration

Equation of motion

v=u+at\\\Rightarrow a=\frac{v-u}{t}\\\Rightarrow a=\frac{5.91-6.75}{2.5}\\\Rightarrow a=-0.336\ m/s^2

v^2-u^2=2as\\\Rightarrow s=\frac{v^2-u^2}{2a}\\\Rightarrow s=\frac{5.91^2-6.75^2}{2\times -0.336}\\\Rightarrow s=15.825\ m

The distance Rickey slides across the ground before touching the base is 15.825 m

4 0
3 years ago
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