We see black colour in absence of light. Black colour absoorbs all the light, ( just opposite of white) and hence we do not see any colour. Black colour is also related to darkness.
The <span>flow of how a cold pack works on a sprained ankle is based on the second law of thermodynamics which states that energy will flow from a higher to a lower temperature. So your body heat will flow to the cold pack in which you will feel the coldness of the pack.</span>
Answer:
<em>The second option has a lower power output. P=30 W</em>
Explanation:
<u>Mechanical Power
</u>
It is a physical magnitude that measures the rate a work W is done over time t.
Since W=F.d
The first option means the worker will lift the box by a distance of 1.2 meters in 3 seconds by applying 250 N of force. That produces a power of
The second option requires the worker applies 75 N of force and travel a distance of 4 meters for 10 seconds, thus the power is
The second option has a lower power output
Answer:
Explanation:
The change is as follows
P₁ V₁ to 3P₁, V₁ ( constt volume ) --- first process
3P₁,V₁ to 3P₁ , 5V₁ ( constt pressure ) ---- second process
In the first process Temperature must have been increased 3 times . So if initial temperature is T₁ then final temperature will be 3 T₁
P₁V₁ = n R T₁ , n is no of moles of gas enclosed.
nRT₁ = P₁V₁
Heat added at constant volume = n Cv ( 3T₁ - T₁)
= n x 5/3 R X 2T₁ ( for diatomic gas Cv = 5/3 R)
= 10/3 x nRT₁
= 10/3x P₁V₁
In the second process, Temperature must have been increased 5 times . So if initial temperature is 3T₁ then final temperature will be 15 T₁
Heat added at constant pressure in second case
= n Cp ( 15T₁ - 3T₁)
= n x 7/3 R X 12T₁ ( For diatomic gas Cp = 7/3 R)
= 28 x nRT₁
= 28 P₁V₁
Before Copernicus most people were thinking that the Earth is at center of universe. In 1609 Galileo observed sky through his home made telescope.
He found 4 moons orbiting Jupiter..It was a proof that bodies are orbiting other planets and not earth alone. <span>He found the crescent shape of Venus through his telescope and this could happen only if Sun is at center.</span>
