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QveST [7]
3 years ago
9

WORTH 50 POINTS

Physics
2 answers:
Mice21 [21]3 years ago
8 0
1) We have that temperature naturally flows from areas that are hot to areas that are cold (this is a consequence of the 2nd law of thermodynamics). But this can change if we do not have a closed system, hence if we can change some of the conditions. A good completion would be: is possible only if the system is not closed/we add energy.
2) Air is apoor conductor and sunlight has barely enough concnetrated energy to make a heat pump work adequately. However, all other choices have worked. Hot water is used in several nuclear plant for heat pumps, fires are also used in simple mechanical systems and the ground heat has been used in hydrothermal vents etc.
3) A bimetallic coil is a coil that exemplifies the expansion of metals in the presence of heat and acts like an inaccurate thermometer. Since different metals expand at different speeds, the coil expands unequally when heated and ends up stretching.
4) Out of the 4 choices, refrigeration and coolant are inappropriate choices since they do not refer to release of hit but getting rid of heat. The thermostat also does not burn fuel, it jsut observes temperature. The correct answer is combustion which is defined as a cheical reaction that gives off heat and flame.
5) A heat engine by definitions converts heat into mechanical energy. We have that the only of the choices above that has as a product mechanical energy is the choice with the car, hence this is correct. An air conditioner is a heat pump, not a heat engine.
7) We have that by the law of chemistry, PV=nRT. and that the thermal energy is proportional to T. The pressure cannot increase without stop, so what we have when the temperature (thermal energy) goes up is that the volume also goes up. Hence, the correct answer is that an increase in thermal energy leads to an increase in pressure.
barxatty [35]3 years ago
5 0

The answer to question 7 would be D.


In the future, only put one question per question on Brainly. :)

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Which force diagram accurately represents a satellite in orbit around Earth?
Anit [1.1K]

Answer:

First choice

Explanation:

A satellite in orbit around Earth experiences only one force: the gravitational attraction exerted by the Earth on it. This force is labelled with F_g. In space, there are no other forces acting on the satellite.

The force of gravity acts as centripetal force, "pulling" the satellite towards the centre of its circular orbit. The inertia of the satellite (which has an initial velocity) tends to keep it moving straight, so the combination of these two effects (inertia and force of gravity) results into the circular motion of the satellite.

5 0
3 years ago
Read 2 more answers
The force of replusion between two like charged particles will increase if​
Alex_Xolod [135]

Answer:

The distance of separation is decreased

Explanation:

From Cuolomb's law, we know that the strength of charge is inversely proportional to the distance of separation between the charges. To mean that increasing the distance let's say from 2m to 3 m would mean initial strength getting form 1/4 to 1/9 which is a decrease. The vice versa is true hence the force of repulsion can increase only when we decrease the distance of separation.

7 0
3 years ago
A motorcycle being driven on a dirt path hits a
Colt1911 [192]
Impulse = mass * change in velocity (change in momentum) = Force * change in time

So, F=(m*change in v)/(change in t)
F=(60*20)/0.5=2400N

Therefore the magnitude of the average force exerted on the cyclist by the haystack is 2.4*10^3N
4 0
4 years ago
The activation energy of a certain reaction is 37.2 kJ/mol . At 20 ∘C, the rate constant is 0.0130 s−1. At what temperature woul
Butoxors [25]

Answer: At 34°c

Explanation:

Using The Arrhenius Equation:

k = Ae − Ea/RT

k represents rate constant

A represents frequency factor and is constant

R represents gas constant which is = 8.31J/K/mol

Ea represents the activation energy

T represents the absolute temperature.

By taking the natural log of both sides,

ln k = ln A- Ea/RT

Reactions at temperatures T1 and T2 can be written as;

ln k1= ln A− Ea/RT1

ln k2= ln A− Ea/RT2

Therefore,

ln(k1/k2) = −Ea/RT1 + Ea/RT2

Since k2=2k1 this becomes:

ln(1/2) = Ea/R*[1/T2 − 1/T1]

Theefore,

-0.693 = 37.2 x 10^3/8.31 * [ 1/T2 - 1/293]

1/T2 - 1/293 = -1.55 x 10^-4

1/T2 = -1.55 x 10^-4 + 34.13x 10^-4

1/T2 = 32.58 x 10^-4

Therefore T2 = 307K

T2 = 307 - 273 = 34 °c

7 0
3 years ago
For a transverse wave, what is a wavefront?
vichka [17]

Explanation:

A wavefront is the long edge that moves, for example, the crest or the trough. Each point on the wavefront emits a semicircular wave that moves at the propagation speed v. These are drawn at a time t later, so that they have moved a distance s = vt.

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3 years ago
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