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ira [324]
3 years ago
9

TEST HELP PLEASE!! WILL GIVE MEDAL TO BEST ANSWER!!

Physics
2 answers:
Veronika [31]3 years ago
7 0
C. Hot air balloons use convection to rise.
Law Incorporation [45]3 years ago
7 0
<span>hot air balloons rise due to convection. Hot air is less dense than cool air; the heated air causes the balloon to rise simply because it is lighter than an equal volume of cold air. the transfer of heat from flame to air is the convection process.</span>
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A mass is oscillating with amplitude A at the end of a spring.
Dmitry_Shevchenko [17]

A) x=\pm \frac{A}{2\sqrt{2}}

The total energy of the system is equal to the maximum elastic potential energy, that is achieved when the displacement is equal to the amplitude (x=A):

E=\frac{1}{2}kA^2 (1)

where k is the spring constant.

The total energy, which is conserved, at any other point of the motion is the sum of elastic potential energy and kinetic energy:

E=U+K=\frac{1}{2}kx^2+\frac{1}{2}mv^2 (2)

where x is the displacement, m the mass, and v the speed.

We want to know the displacement x at which the elastic potential energy is 1/3 of the kinetic energy:

U=\frac{1}{3}K

Using (2) we can rewrite this as

U=\frac{1}{3}(E-U)=\frac{1}{3}E-\frac{1}{3}U\\U=\frac{E}{4}

And using (1), we find

U=\frac{E}{4}=\frac{\frac{1}{2}kA^2}{4}=\frac{1}{8}kA^2

Substituting U=\frac{1}{2}kx^2 into the last equation, we find the value of x:

\frac{1}{2}kx^2=\frac{1}{8}kA^2\\x=\pm \frac{A}{2\sqrt{2}}

B) x=\pm \frac{3}{\sqrt{10}}A

In this case, the kinetic energy is 1/10 of the total energy:

K=\frac{1}{10}E

Since we have

K=E-U

we can write

E-U=\frac{1}{10}E\\U=\frac{9}{10}E

And so we find:

\frac{1}{2}kx^2 = \frac{9}{10}(\frac{1}{2}kA^2)=\frac{9}{20}kA^2\\x^2 = \frac{9}{10}A^2\\x=\pm \frac{3}{\sqrt{10}}A

3 0
3 years ago
If we decrease the amount of force, and kelp all other factors the same, what will happen to the amount of work?
Artist 52 [7]

Answer:

Distance will decrease and work will decrease:

F = m a      Newton's Second Law

a = F / m       decreasing force will decrease acceleration

S = 1/2 a t^2 = 1/2 (F / m) t^2     distance traveled will decrease as force        decreases

W = F * S       work will decrease as both force and distance decrease

8 0
3 years ago
Soot particles ("black carbon aerosols" generally cause ________ of earth's atmosphere by ________ solar energy.
matrenka [14]
They cause an increase in temp of earths atmosphere or warming by absorbing solar energy. hope this helps
8 0
3 years ago
A proposed ocean thermal-energy conversion (OTEC) system is a heat engine that would operate between warm water (16°C) at the oc
LenaWriter [7]

Answer:

3.46 %

Explanation:

We have given cooler temperature that is T_c = 6°C =273+6=279 K

And the warm temperature of water that is T_h=16^{\circ}C=16+273=289\ K

The maximum possible efficiency is given by \eta =1-\frac{T_c}{T_h}

So maximum efficiency \eta =1-\frac{T_c}{T_h}=1-\frac{279}{289}=0.0346=3.46 %

6 0
2 years ago
A. Which of the four thermal processes describes the pressure-volume relationship at a constant temperature?
lara31 [8.8K]
The thermal process that occurs when pressure and volume are variable, while the temperature remains constant is known as an isothermal process. Due to the change in temperature being zero, the internal energy of the system does not change. Isothermal processes can be carried out adiabatically or non-adiabatically. (An adiabatic process is where the heat energy moving through the boundary of a system is 0)
4 0
3 years ago
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