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Deffense [45]
3 years ago
8

Buna! Am nevoie urgent va rog de ajutor la aceste 2 ex:

Physics
1 answer:
Gemiola [76]3 years ago
7 0

Explanation:

rent me for brainliest pls

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A 63-kg hiker is climbing the 828-m-tall Burj Khalifa in Dubai. If the efficiency of converting the energy content of the bars i
konstantin123 [22]

Answer:

T_f=5854.76 °C

Explanation:

Given:

mass of hiker, m= 63 kg

height to be climbed, h= 828 m

energy produced by an energy bar, E= 1.10\times 10^6 J

heat capacity of the hiker, c=75.3 J.mol^{-1}.K^{-1}= 4.184 J.kg^{-1}.K^{-1}

initial body temperature of hiker, T_i=36.6 \degree C

<em>The efficiency of converting the energy content of the bars into the work of climbing is 25%, the remaining 75% of the energy released through metabolism is heat released to her body.</em>

We find the energy required for climbing 828 m height:

W=m.g.h

W=63\times 9.8\times 828

W= 511207.2 J

∵Hike eats 2 energy bars= 2\times 1.1\times 10^{6} J

Energy produced= 2.2\times 10^{6} J

Now, according to her efficiency:

Total energy required for producing the work of W= 511207.2 J which is required to climb the given height will be (say, E):

25\% of E= 511207.2

\Rightarrow E= 511207.2\times \frac{100}{25}

E=2044828.8 J

&

Amount of total energy (E) converted into heat(Q) is:

Q=2044828.8-511207.2\\Q=1533621.6J

As we know that:

heat, Q=m.c. (T_f-T_i).................(1)

where:

T_f is the final temperature

Putting respective values in the eq. (1)

1533621.6= 63\times 4.184\times (T_f-36.6)

(T_f-36.6)\approx 5818.16

T_f\approx 5854.76 °C

4 0
3 years ago
Why does atomic radius decrease from left to right?
victus00 [196]
Because the effective charge of the nucleus increase from left to eight due to the increasing number of protons.

The greater charge pulls the electrons closer to the nucleus, decreasing the radius.
7 0
4 years ago
4: Which of the following is true of an object in a circular motion at a constant speed?
kaheart [24]
C. The object is accelerating as the direction of the object is changing
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3 years ago
Will Give Brainlist <br> Check pic for question
Harrizon [31]
Ohms law = v= Ir

V= 0.02 x 4000 = 80v
5 0
3 years ago
Read 2 more answers
An ideal gas occupies a volume of 0.60 m3 at 5.0 atm and 400. K. What volume does it occupy at 4.0 atm and a temperature of 200.
kotegsom [21]
V1 = 0.60 m3, P1 = 5.00atm, T1=400K
V2 = ??m3, P2 = 4.00atm, T2=200K
P1V1/T1 = P2V2/T2
V2 = T2P1V1/T1P2 = 200×5×0.60/400×4.00 = 600/1600
V2 = 0.38 m3
7 0
3 years ago
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