All categories

3 years ago

Why does a hot-air balloon rise?

Physics

1 answer:

prohojiy [21]3 years ago

4 0

Answer: The weight of the air displaced by the balloon is less than the volume of the balloon.

Explanation:

A hot air balloon is a cloth wrap that contains several thousand cubic meters of air inside (a large volume of air). The burner heats the liquid propane to a gaseous state to generate a huge flame, which can reach more than 3 meters, thus heating the air mass inside the balloon. In this way, its density is modified with respect to the air that surrounds it, because the hot air is lighter than the outside air (less dense), causing the balloon to rise and float.

Now, if we know that the density of a body $d$ is directly proportional to its mass $m$ and inversely proportional to its volume $V$ :

$d=\frac{m}{V}$

We can deduce that by increasing the volume of the body, its density will decrease.

This is proof of Archimedes' Principle:

A body totally or partially immersed in a fluid at rest, experiences a vertical upward thrust equal to the mass weight of the body volume that is displaced.

In this case the fluid is the air outside. So, the warm air inside the balloon, being less dense, will weigh less than the outside air and therefore will receive an upward pushing force or thrust that will make the balloon ascend.

You might be interested in

The coefficient of performance of a residential heat pump is 1.6. Calculate the heating effect in kJ/s this heat pump will produ

grin007 [14]

Answer:

8 KJ/ s

Explanation:

Heat pumps Transfer thermal energy through absorbing of heat that comes from cold region and then release to warmer area by utilizing external power.

The coefficient of performance known as COP provide the ratio of both heating and cooling that are supplied to required work.

✓QH=The rate at which heat is produced = ?

✓COP= Coefficient of performance of a residential heat pump = 1.6

✓ W(in)= power consumption= 5KW

QH=The rate at which heat is produced=[Coefficient of performance of a residential heat pump] × [power consumption]

= 1.6 × 5KW

=8 KJ/ s

7 0

3 years ago

I need homework help

KIM [24]

1) the weight of an object at Earth's surface is given by $F=mg$ , where m is the mass of the object and $g=9.81 m/s^2$ is the gravitational acceleration at Earth's surface. The book in this problem has a mass of m=2.2 kg, therefore its weight is
$F=mg=(2.2 kg)(9.81 m/s^2)=21.6 N$

2) On Mars, the value of the gravitational acceleration is different: $g=3.7 m/s^2$ . The formula to calculate the weight of the object on Mars is still the same, but we have to use this value of g instead of the one on Earth: $F=mg=(2.2 kg)(3.7 m/s^2)=8.1 N$

3) The weight of the textbook on Venus is F=19.6 N. We already know its mass (m=2.2 kg), therefore by re-arranging the usual equation F=mg, we can find the value of the gravitational acceleration g on Venus:
$g= \frac{F}{m}= \frac{ 19.6 N}{2.2 kg}=8.9 m/s^2$

4) The mass of the pair of running shoes is m=0.5 kg. Their weight is F=11.55 N, therefore we can find the value of the gravitational acceleration g on Jupiter by re-arranging the usual equation F=mg:
$g= \frac{F}{m} = \frac{11.55 N}{0.5 kg} =23.1 m/s^2$

5) The weight of the pair of shoes of m=0.5 kg on Pluto is F=0.3 N. As in the previous step, we can calculate the strength of the gravity g on Pluto as
$g= \frac{F}{m} = \frac{0.3 N}{0.5 kg} =0.6 m/s^2$

6) On Earth, the gravity acceleration is $g=9.81 m/s^2$ . The mass of the pair of shoes is m=0.5 kg, therefore their weight on Earth is
 $F=mg=(0.5 kg)(9.81 m/s^2)=4.9 N$

5 0

3 years ago

Why does the entropy of a gas increase when it expands into a vacuum? Why does the entropy of a gas increase when it expands int

Mrrafil [7]

Answer:

The entropy of a gas increases when it expands into a vacuum because the number of possible states increases .

Explanation:

When a gas expand in a vacuum, the molecules of the gases vibrates very fast and starting moving with higher velocity in random directions which means the level of disorder in the gases increases.

Now the possible state of the gas molecule increases such as the particle can be located at different position due to increased randomness.

Entropy is the measure of this randomness and thus with this increased randomness entropy also increases.

6 0

3 years ago

The mass of an object changes as the distance from the center of gravity changes.

Alchen [17]

Answer:

true

Explanation:

this is the answer to this question

8 0

3 years ago

Define prism and itz colo plz tell me fast

Andrei [34K]

Answer:

A prism is a clear crystal that refracts light

Explanation:

7 0

3 years ago

Read 2 more answers