6. A girl pushes her little brother on his sled with a force of 300 N for 750 m.

Explain, using the kinetic theory of matter, why liquids and solids are more denser than gases

AlekseyPX

Solid and liquids are much more denser than gas because their molecules are close to each other and with that the molecules of them can't move that freely unlike the gas molecules. Also, because of being near to each other the molecules of solid and liquids became heavy making them dense.

5 0

3 years ago

A 650 kg steel beam is being pulled up by a crane with a force of 7020 N. What is the upwards acceleration of the beam?

zimovet [89]

Answer: 1 m/s^2

Explanation:

n= w+ma

n= Mg+Ma

7020 = (650)(9.8)+650a

7020 = 6370+ 650a

650=650a

A= 1 m/s^2

8 0

3 years ago

We are going to make an imaginary engine using water. We are going to heat 100 grams of water to 120 C from its initial temperat

Svetach [21]

Answer:

The work done by this engine is 800 cal

Explanation:

Given:

100 g of water

120°C final temperature

22°C initial temperature

30°C is the temperature of condensed steam

Cw = specific heat of water = 1 cal/g °C

Cg = specific heat of steam = 0.48 cal/g °C

Lw = latent heat of vaporization = 540 cal/g

Question: How much work can be done using this engine, W = ?

First, you need to calculate the heat that it is necessary to change water to steam:

$Q_{1} =m_{w} C_{w} (100-22)+m_{w}L_{w}+m_{w}C_{g}(120-100)$

Here, mw is the mass of water

$Q_{1} =(100*1*78)+(100*540)+(100*0.48*20)=62760cal$

Now, you need to calculate the heat released by the steam:

$Q_{2} =m_{w}C_{g}(120-100)+m_{w}L_{w}+m_{w}C_{w}(100-30)=(100*0.48*20)+(100*540)+(100*1*70)=61960cal$

The work done by this engine is the difference between both heats:

$W=Q_{1}-Q_{2}=62760-61960=800cal$

8 0

3 years ago

which statements about acceleration are true? check all that apply. a. the si units of acceleration are m/s2. b. for acceleratio

tatiyna

The first thing you should know is that acceleration is a vector, therefore, it has magnitude, and direction.

By definition, we have that the vector acceleration is given by:

$a = \frac{dv}{dt}\\$

Where,

dv/dt: derived from the velocity vector with respect to time,

Therefore, the units of the vector acceleration are:

$a = \frac{\frac{m}{s}}{s}\\$

$a = \frac{m}{s^2}$

The symbol of acceleration is:

$a^{->}$

Answer:

The statements about acceleration that are true are:

a. the si units of acceleration are m/s2.

b. for acceleration, you must have a number, a unit, and a direction.

d. the symbol for acceleration is (True, only if the symbol is the same as above)

5 0

3 years ago

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Crystals are made using supersaturated solutions of solids in water.

labwork [276]

The way these supersaturated solutions are made is: A. The water would need to be heated to a higher temperature, which would give molecules and ions more kinetic energy, increasing solubility.

Solubility is simply a measure of how readily a substance is able to dissolve in a solvent to form a solution. Thus, a substance is soluble when it dissolves completely in a solvent and it is considered to be insoluble when it does not dissolve in a solvent or if it only dissolves partially.

A supersaturated solution can be defined as a solution that contains more solute than the equilibrium amount.

Generally, supersaturated solutions of solids in water are typically used for the creation of crystals because they are able to hold more of the solute than they would at room temperature.

In order to create these supersaturated solutions, the water should be heated to a higher temperature, so that the water molecules and ions can gain more kinetic energy and thereby increasing solubility.

In conclusion, heating the water to a higher temperature causes the water molecules and ions to gain more kinetic energy and thereby increasing solubility..

8 0

3 years ago

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