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Eduardwww [97]
3 years ago
10

Two Questions Worth 14 points(Gradpoint)

Physics
1 answer:
Liula [17]3 years ago
7 0
<span>1. Pu-239 has a half-life of _____.
</span>  24,100 years
2. <span>Nuclear fusion has not yet been harnessed as an energy source because _____.</span>
a.sufficient pressure cannot be generated  
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A particular car engine operates between temperatures of 440°C (inside the cylinders of the engine) and 20°C (the temperature of
Step2247 [10]

One of the concepts to be used to solve this problem is that of thermal efficiency, that is, that coefficient or dimensionless ratio calculated as the ratio of the energy produced and the energy supplied to the machine.

From the temperature the value is given as

\eta = 1-\frac{T_L}{T_H}

Where,

T_L = Cold focus temperature

T_H = Hot spot temperature

Our values are given as,

T_L = 20\° C = (20+273) K = 293 K

T_H = 440\° C = (440+273) K = 713 K

Replacing we have,

\eta = 1-\frac{T_L}{T_H}

\eta = 1-\frac{293}{713}

\eta = 0.589

Therefore the maximum possible efficiency the car can have is 58.9%

4 0
3 years ago
Hi Guys.I was just wondering if given two specific heat capacities (In my case copper and water) do you add them both together o
timama [110]

Answer:

yes

Explanation:

using law of HC(heat capacity), which is

  • heat loss=heat gain
  • energy H=MCQ

Where M is mass of substance,C is specific heat capacity, and Q is temperature change

In case of two substance

  • the H = Mc*Cc*Q+Mw*Cw*Q(provided the initial and final temperature are given)

8 0
3 years ago
What is the average velocity of the object from t=1s to t= 3 s?
galina1969 [7]

Answer:

Explanation:

Since this is a distance v time graph, the slope of the line from 1s to 3s is the velocity. However, it looks like, at t=3, the velocity is 0, so getting the definite velocity is not going to happen. We can estimate it as closely as possible. Since the line is tending from the upper left to the lower right, the slope is negative, so the velocity is also negative. That leaves only C or D as our answers. And the slope is closer to -1 than to -5, so choice D. is the one you want.

7 0
3 years ago
Gases, just like liquids are made of particles which can be further classified as atoms or molecules,
olga_2 [115]

Answer:

True

Explanation:

Solids, Liquids, and Gases are all make up of <u><em>atoms and molecules. </em></u>

8 0
3 years ago
If I rub a polythene piece with a wool , is there a transfer of mass from wool to polythene?​
kirill [66]

Yes, As a result, wool is positively charged while polythene is negatively charged. As a result, 1.87 1012 electrons have been transported from wool to polythene. As a result, only a sliver of mass is transferred from wool to polythene.

8 0
3 years ago
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