All categories

3 years ago

How does a vacuum flask keep drinks hot? Explain in terms of conduction, convection and radiation.

1 answer:

4 0

Vacum flask has inner layer of glass and outer body of plastic.the glass has a reflective metal layer..when a hot drink is poured into the flask it prevents conduction.tight lid stops the convection.when radiation tries to leave the hot drink the reflective layer of the glass reflects it back so no heat can escape.

You might be interested in

The established value for the speed of light in a vacuum is 299,792,458 m/s. What is the order-of-magnitude of this number?

iogann1982 [59]

The order of magnitude is 10⁸ .

6 0

3 years ago

what is the mechanical advantage of a crowbar when a worker uses 10N of force to pry open a window that has a resistance of 500N

Oksana_A [137]

Answer:

Explanation:

The mechanical advantage of a machine is given by

$MA=\frac{F_{out}}{F_{in}}$

where

$F_{out}$ is the output force

$F_{in}$ is the input force

For the crowbar in this problem,

$F_{in}=10 N$ is the force in input applied by the worker

$F_{out}=500 N$ is the force that the machine must apply in output to overcome the resistance of the window and to open it

Substituting into the equation, we find

$MA=\frac{500}{10}=50$

3 0

3 years ago

Read 2 more answers

Examine the lightbulbs in the circuit below. Write a sentence explaining what would happen if lightbulb A burned out. Repeat thi

tatiyna

If the lightbulb A in the circuit shown in the image burned out, the path for the current to flow is disrupted because one of its terminals is connected direct to the source. So, there will be no current through the lightbulbs B, C, and D, and they will turn off. Similarly it will happen, if the lightbulb D burned out.

If the lightbulb B burned out the current will continue circulating through the lightbulbs A, C, and D, because lightbulb B is connected in parallel. Similarly it will happen, if the lightbulb C burned out.

8 0

3 years ago

A cell phone weighing 80 grams is flying through the air at 15 m/s. What is its kinetic energy

Contact [7]

Answer:

The kinetic energy of the cell phone is 9J

Explanation:

The kinetic energy is the energy possessed by a body by virtue of motion.

The kinetic energy is expressed as

KE= 1/2m(v)²

Given data

Mass of cell phone m= 80g--to kg=80/1000= 0.08kg

Velocity of cell phone v= 15m/s

Substituting our given data we have

KE= 1/2*0.08(15)²

KE= (0.08*225)/2

KE=18/2

KE= 9J

8 0

2 years ago

What type of image can a convex mirror produce?

Digiron [165]

Convex mirrors only produce virtual images

7 0

3 years ago

Read 2 more answers