All categories

2 years ago

Your friend says their laptop speakers

1 answer:

5 0

The sound comes from the speakers which produce sound waves which is the music, the volume could be changed producing a louder sound or a quieter sound which means that the speakers could produce more sound waves or less sound ways ( depends on the volume )

You might be interested in

A cold beverage can be kept cold even a warm day if it is slipped into a porous ceramic container that has been soaked in water.

Arisa [49]

Answer:

The rate at which the container is losing water is 0.0006418 g/s.

Explanation:

Under the assumption that the can is a closed system, the conservation law applied to the system would be: $E_{in}-E_{out}=E_{change}$ , where $E_{in}$ is all energy entering the system, $E_{out}$ is the total energy leaving the system and, $E_{change}$ is the change of energy of the system.
As the purpose is to kept the beverage can at constant temperature, the change of energy ( $E_{change}$ ) would be 0.
The energy that goes into the system, is the heat transfer by radiation from the environment to the top and side surfaces of the can. This kind of transfer is described by: $Q=\varepsilon*\sigma*A_S*(T_{\infty}^4-T_S^4)$ where $\varepsilon$ is the emissivity of the surface, $\sigma=5.67*10^{-8}\frac{W}{m^2K}$ known as the Stefan–Boltzmann constant, $A_S$ is the total area of the exposed surface, $T_S$ is the temperature of the surface in Kelvin, $T_{\infty}$ is the environment temperature in Kelvin.
For the can the surface area would be ta sum of the top and the sides. The area of the top would be $A_{top}=\pi* r^2=\pi(0.0252m)^2=0.001995m^2$ , the area of the sides would be $A_{sides}=2*\pi*r*L=2*\pi*(0.0252m)*(0.09m)=0.01425m^2$ . Then the total area would be $A_{total}=A_{top}+A_{sides}=0.01624m^2$
Then the radiation heat transferred to the can would be $Q=\varepsilon*\sigma*A_S*(T_{\infty}^4-T_S^4)=1*5.67*10^{-8}\frac{W}{m^2K}*0.01624m^2*((32+273K)^4-(17+273K)^4)=1.456W$ .
The can would lost heat evaporating water, in this case would be $Q_{out}=\frac{dm}{dt}*h_{fg}$ , where $\frac{dm}{dt}$ is the rate of mass of water evaporated and, $h_{fg}$ is the heat of vaporization of the water ( $2257\frac{J}{g}$ ).
Then in the conservation balance: $Q_{in}-Q_{out}=Q_{change}$ , it would be $1.45W-\frac{dm}{dt}*2257\frac{j}{g}=0$ .
Recall that $1W=1\frac{J}{s}$ , then solving for $\frac{dm}{dt}$ : $\frac{dm}{dt}=\frac{1.45\frac{J}{s} }{2257\frac{J}{g} }=0.0006452\frac{g}{s}$

5 0

2 years ago

Most reactive non-metals in order?

kompoz [17]

Nonmetals often share or gain electrons. The nonmetals in the periodic table increases as you move to the right and decreases as you go down. This is because, the smaller the atom, the reactive it gets due to less electron attached to the orbits of the atom. The reactivity of nonmetals is arranged in decreasing order. 
Carbon
 Nitrogen
Oxygen
Fluorine
Phosphorus 
Sulfur
Chlorine 
Selenium 
Bromine 
Iodine

5 0

2 years ago

A spy in a speed boat is being chased down a river by government officials in a faster craft. Just as the officials’ boat pulls

babunello [35]

Answer:

They are 7.4m apart.

Explanation:

Here we have a parabolic motion problem. we need the time taken to land so:

$Y=Yo+Vo*t+\frac{1}{2}*a*t^2$

considerating only the movement on Y axis:

$0=4.6-(9.81)*t^2\\t=0.68s$

Because we have a contant velocity motion on X axis:

$xs=vs*t\\xs=17m/s*(0.68s)\\xs=11.6m$

and

$xg=vg*t\\xg=28m/s*(0.68s)\\xg=19m$

the distance between them is given by:

$d=|xg-xs|\\d=7.4m$

7 0

2 years ago

A scientist kept 1,000 grams of a radioactive material in a container. After 66 days, he observed that 125 grams of the radioact

bixtya [17]

The sample appears to have gone through 3 half-lives
1st half life: 1000 to 500 g
2nd half life: 500 to 250 g
3rd half life: 250 to 125 g
The duration of a half-life, therefore, can be inferred to be 66 ÷ (3) = 22 days.

After a 4th half life, there will be 125÷2= 62.5 g.
At this point, an additional 22 days will have passed, for a total of 88 days.
Answer is C.

8 0

2 years ago

Please help me with this question,giving the first correct answer brainliest

elena-s [515]

Answer:

Explanation:

4 0

1 year ago

Read 2 more answers