True or false if an object has energy it must be moving

2 answers:

8 0

False. Non moving objects can have energy in the form of gravitational potential energy, elastic potential energy, thermal energy, internal energy, nuclear energy, or chemical energy.

Drupady [299]3 years ago

3 0

Answer:

Explanation:

If an object is moving, it is said to have kinetic energy (KE). Potential energy (PE) is energy that is "stored" because of the position and/or arrangement of the object. The classic example of potential energy is to pick up a brick. When it's on the ground, the brick had a certain amount of energy.

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__________________________ are made of rock or metal, which often collide with Earth

konstantin123 [22]

Answer:

Planets are bodies of rock or gas that are named after ancient gods.

Asteroids and Meteoroids are made of rock or metal, which often collide with Earth.

The terrestrial planets are more like the Earth.

The Juno spacecraft is exploring the planet Jupiter.

Explanation:

The planets and other stars in our solar system were similarly baptized. The planets were named after ancient gods. Other stars were baptized with names chosen by scientists or according to their peculiarity. Most of the planets were baptized by ancient Chinese astronomers, and later, by Babylonians. But over time different civilizations changed the names of the planets.

An asteroid is a smaller body in the solar system, usually on the order of just a few hundred kilometers. Meteoroids, in turn, are fragments of rocks that form from comets and asteroids. The luminous effect is produced when fragments of celestial bodies ignite in contact with the Earth's atmosphere due to friction. Both asteroids and meteoroids are made of rock or metal, which often collide with Earth.

The terrestrial planets are the most similar to the earth. These planets are those formed mainly by rocks and metals, have a solid surface without the incidence of rings, as is the case with Mercury, Venus and Mars.

The Juno spacecraft is exploring the planet Jupiter. This probe has already given us several unprecedented discoveries about the largest gas giant in the Solar System, in addition to sending us sensational images showing the complex and beautiful atmosphere of the planet.

6 0

3 years ago

Read 2 more answers

Steam enters the condenser of a steam power plant at 20kPa and a quality of 95% with a mass flow rate of 20,000kg/h. It is to be

avanturin [10]

Answer:

The mass rate of the cooling water required is: $1'072988.5\frac{kg}{h}$

Explanation:

First, write the energy balance for the condensator: The energy that enters to the equipment is the same that goes out from it; consider that there is no heat transfer to the surroundings and kinetic and potential energy changes are despreciable.

${m_{w}}*{h_{w}}^{in}+m_s{h_{s}}^{in}=m_w{h_{w}}^{out}+m_s{h_{s}}^{out}$

Where w refers to the cooling water and s to the steam flow. Reorganizing,

$m_w({h_{w}}^{out}-{h_{w}}^{in})=m_s({h_{s}}^{in}-{h_{s}}^{out})\\m_w=\frac{m_s({h_{s}}^{in}-{h_{s}}^{out})}{({h_{w}}^{out}-{h_{w}}^{in})}$

Write the difference of enthalpy for water as Cp (Tout-Tin):

$m_w=\frac{m_s({h_{s}}^{in}-{h_{s}}^{out})}{C_{pw}({T_{w}}^{out}-{T_{w}}^{in})}$

This equation will let us to calculate the mass rate required. Now, let's get the enthalpy and Cp data. The enthalpies can be read from the steam tables (I attach the tables I used). According to that, ${h_{s}}^{out}=251.40\frac{kJ}{kg}$ and ${h_{s}}^{in}$ can be calculated as:

${h_{s}}^{in}={h_{f}}+x{h_{fg}}=251.40+0.95*2358.3=2491.8\frac{kJ}{kg}$ .

The Cp of water at 25ºC (which is the expected average temperature for water) is: 4.176 $\frac{kJ}{kgK}$ . If the average temperature is actually different, it won't mean a considerable mistake. Also we know that ${T_{w}}^{out}-{T_{w}}^{in}\leq 10$ , so let's work with the limit case, which is ${T_{w}}^{out}-{T_{w}}^{in}=10$ to calculate the minimum cooling water mass rate required (A higher one will give a lower temperature difference as a result). Finally, replace data: