Ask question

Ask question

All categories

3 years ago

13

Cooling systems, such as air conditioners and refrigerators, transfer thermal energy in order to keep homes and cars cool or to

keep food cold. In a refrigerator, for example, thermal energy is transferred from the cool air inside the refrigerator to the warmer air in the kitchen. Thermal energy naturally moves from a warmer area to a cooler area, so how can it move from the cooler refrigerator to the warmer room?

1 answer:

Lubov Fominskaja [6]3 years ago

8 0

Answer: I think maybe thru Convection?

Explanation:

cause convection causes the heat to stay to the top and the cold air stay's to the bottom so maybe i would say Convection.... Is there any answer choices?

You might be interested in

scientists use critical thinking skills throughout the process of research or information a student noticed that their energy le

Ganezh [65]

The critical thinking step has the student just completed in the situation describe when the student concluded that soda intake really does have an effect on their energy level is the analysis. This is because the student observed the effects of drinking soda by his experience.

5 0

3 years ago

If the mass of a

mixer [17]

Answer:

The final acceleration becomes (1/3) of the initial acceleration.

Explanation:

The second law of motion gives the relationship between the net force, mass and the acceleration of an object. It is given by :

$F=ma$

m = mass

a = acceleration

According to given condition, if the mass of a sliding block is tripled while a constant net force is applied. We need to find how much does the acceleration decrease.

$a=\dfrac{F}{m}$

Let a' is the final acceleration,

$a'=\dfrac{F}{m'}$

m' = 3m

$a'=\dfrac{F}{3m}$

$a'=\dfrac{1}{3}\times \dfrac{F}{m}$

$a'=\dfrac{1}{3}\times a$

So, the final acceleration becomes (1/3) of the initial acceleration. Hence, this is the required solution.

5 0

3 years ago

Assume that the turntable deccelerated during time Δt before reaching the final angular velocity ( Δt is the time interval betwe

Zina [86]

Answer:

See below...

Explanation:

Let’s express ⟨α⟩ in terms of ωi , ωf , and Δt. and torque in terms of It , ωi , ωf , and Δt.

STEP 1.

The rate of change of angular velocity is Angular acceleration.

The net change in angular velocity is Average angular acceleration divided by the elapsed time.

⟨α⟩ = ω f −ω i/Δt

STEP 2.

Torque is assumed this way

dω

τ = I ----

dt

.

⟨τ ⟩ = I t (ω f −ω i )/Δt

6 0

3 years ago

An atom of carbon has a radius of 67.0 pm and the average orbital speed of the electrons in it is about 1.3 x 10⁶ m/s.

adoni [48]

Answer :

The least possible uncertainty in an electron's velocity is, $4.32\times 10^{5}m/s$

The percentage of the average speed is, 33 %

Explanation :

According to the Heisenberg's uncertainty principle,

$\Delta x\times \Delta p=\frac{h}{4\pi}$ ...........(1)

where,

$\Delta x$ = uncertainty in position

$\Delta p$ = uncertainty in momentum

h = Planck's constant

And as we know that the momentum is the product of mass and velocity of an object.

$p=m\times v$

or,

$\Delta p=m\times \Delta v$ .......(2)

Equating 1 and 2, we get:

$\Delta x\times m\times \Delta v=\frac{h}{4\pi}$

$\Delta v=\frac{h}{4\pi \Delta x\times m}$

Given:

m = mass of electron = $9.11\times 10^{-31}kg$

h = Planck's constant = $6.626\times 10^{-34}Js$

radius of atom = $67.0pm=67.0\times 10^{-12}m$ $(1pm=10^{-12}m)$

$\Delta x$ = diameter of atom = $2\times 67.0\times 10^{-12}m=134.0\times 10^{-12}m$

Now put all the given values in the above formula, we get:

$\Delta v=\frac{6.626\times 10^{-34}Js}{4\times 3.14\times (134.0\times 10^{-12}m)\times (9.11\times 10^{-31}kg)}$

$\Delta v=4.32\times 10^{5}m/s$

The minimum uncertainty in an electron's velocity is, $4.32\times 10^{5}m/s$

Now we have to calculate the percentage of the average speed.

Percentage of average speed = $\frac{\text{Uncertainty in speed}}{\text{Average speed}}\times 100$

Uncertainty in speed = $4.32\times 10^{5}m/s$

Average speed = $1.3\times 10^{6}m/s$

Percentage of average speed = $\frac{4.32\times 10^{5}m/s}{1.3\times 10^{6}m/s}\times 100$

Percentage of average speed = 33.2 % ≈ 33 %

Thus, the percentage of the average speed is, 33 %

3 0

3 years ago

1. A 3.5 kg object experiences an acceleration of 0.5 m/s2. What net force does the object experience

Leviafan [203]

Answer:

<h2>1.75 N</h2>

Explanation:

The force acting on an object given it's mass and acceleration can be found by using the formula

force = mass × acceleration

From the question we have

force = 3.5 × 0.5 = 1.75

We have the final answer as

<h3>1.75 N</h3>

Hope this helps you

7 0

2 years ago