When the air density is 0 kg/m°(vacuum), how long will it take an object to reach terminal velocity?
1 answer:
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To solve this problem we will use the concepts related to power, defined as the amount of energy applied over a period of time.
The energy in this case is the accumulated in the form of potential energy, over a period of time. Thus we will have that the mathematical expression of the power can be expressed as
Here,
E = Energy
t = time
As the energy is equal to the potential Energy we have tat
The weight (mg) of the man is 700N, the height (h) is 8m and the time is 10s, then:
Therefore the correct answer is A.
Answer:
The work and heat transfer for this process is = 270.588 kJ
Explanation:
Take properties of air from an ideal gas table. R = 0.287 kJ/kg-k
The Pressure-Volume relation is <em>PV</em> = <em>C</em>
<em>T = C </em> for isothermal process
Calculating for the work done in isothermal process
<em>W</em> = <em>P</em>₁<em>V</em>₁
= <em>mRT</em>₁ [∵<em>pV</em> = <em>mRT</em>]
= (5) (0.287) (272.039)
= 270.588 kJ
Since the process is isothermal, Internal energy change is zero
Δ<em>U</em> =
From 1st law of thermodynamics
Q = Δ<em>U </em>+ <em>W</em>
= 0 + 270.588
= 270.588 kJ