Answer:
The three ways thermal energy is transferred are;
1) Conduction
2) Convection
3) Radiation
Explanation:
1) The conduction of the heat from the open flame to the marshmallow is through the direct contact of the flame with the marshmallow, such that the flame the region of the combustion reaction, that produces light and heat touches the marshmallow
2) The convection process is the transfer of heat from the rising heated combustion products, as well as the heated air that rises from the flame
3) The radiation heat transfer is the transfer of the heat from the fire to the marshmallows directly by the heat the moves in the form of electromagnetic waves at temperatures above 1000 K, without the need for a medium, such that the marshmallow can be heated by the heat coming from side of the flame.
Answer:
if a car is increasing it's acceleration uniformly in a unit time, the graph will be moving away from it's origin. that's how you get this kind of graph.
Answer:
An increase in air temperature because of its compression.
Explanation:
The Gay-Lussac's Law states that a gas pressure is directly proportional to its temperature in an enclosed system to constant volume.
<em>where P: is the gas pressure, T: is the gas temperature and k: is a constant.</em>
Therefore, due to Gay-Lussac's Law, when the plunger is pushed down very rapidly, the pressure of the air increase, which leads to its temperature increase. That is why cotton flashes and burns.
I hope it helps you!
Answer:
a = 0.55 m / s²
Explanation:
The centripetal acceleration is given by the relation
a = v² / r
angular and linear velocities are related
v = w r
we substitute
a = w² r
In the exercise they indicate the angular velocity w = 1 rev/min, let's reduce to the SI system
w = 1 rev / min (2pi rad / 1rev) (1min / 60s) = 0.105 rad/ s
let's calculate
a = 0.105² 50.0
a = 0.55 m / s²
Explanation:
Since, entropy is the measure of degree of randomness. So, more randomly the molecules of a substance are moving more will be its entropy.
- For example, when a solid melts then it means heat is absorbed by it due to which its molecules have gained energy. As a result, they collide with each other and hence, entropy will increase.
- Evaporation of a liquid will also cause the liquid to change its state from liquid to gas. This means molecules will go far away from each other leading to an increase in the entropy.
- Sublimation is a process of conversion of a solid into gaseous phase without going through liquid phase. So, in this case also entropy will increase due to gain in energy by the molecules of a solid.
- In freezing, molecules of a substance come closer to each other and acquire less energy. Hence, entropy decreases.
- Mixing is a process of combining two or more substances physically with each other. This leads to increase in entropy of a substance.
- In separation molecules are separated from each other leading to a decrease in energy. Hence, entropy will also decrease.
- Diffusion is a process in which molecules are able to rapidly move from one place to another. Hence, entropy increases when diffusion takes place.
Thus, we can conclude that melting of a solid, evaporation of a liquid, sublimation, mixing and diffusion involve an increase in the entropy of the system under consideration.
