Answer:
A) 60%
B) p2 = 1237.2 kPa
v2 = 0.348 m^3
C) w1-2 = w3-4 = 1615.5 kJ
Q2-3 = 60 kJ
Explanation:
A) calculate thermal efficiency
Л = 1 -
where Tl = 300 k
Th = 750 k
hence thermal efficiency ( Л ) = [1 - ( 300 / 750 )] * 100 = 60%
B) calculate the pressure and volume at the beginning of the isothermal expansion
calculate pressure ( P2 ) :
= P3v3 = mRT3 ----- (1)
v3 = 0.4m , mR = 2* 0.287, T3 = 750
hence P3 = 1076.25
next equation to determine P2
Qex = p3v3 ln( p2/p3 )
60 = 1076.25 * 0.4 ln(p2/p3)
hence ; P2 = 1237.2 kpa
calculate volume ( V2 )
p2v2 = p3v3
v2 = p3v3 / p2
= (1076.25 * 0.4 ) / 1237.2
= 0.348 m^3
C) calculate the work and heat transfer for each four processes
work :
W1-2 = mCv( T2 - T1 )
= 2*0.718 ( 750 - 300 ) = 1615.5 kJ
W3-4 = 1615.5 kJ
heat transfer
Q2-3 = W2-3 = 60KJ
Q3-4 = 0
D ) sketch of the cycle on p-V coordinates
attached below
The statement ‘Big bang theorists
believe that the universe is expanding and will eventually contract’ is false. The
answer is letter B. The big bang theory suggests that the origin of the
universe began with that exploded and expanded. It also states that the
universe began in a single form of high condensed reactive matter and exploded
forming the galaxies, planets, stars and other celestial bodies.
Answer:
21.28 m
Explanation:
height, h = 71 m
velocity of raft, v = 5.6 m/s
let the time taken by the stone to reach to raft is t.
use second equation of motion for stone
u = 0 m/s, h = 71 m, g = 9.8 m/s^2
71 = 0 + 0.5 x 9.8 x t^2
t = 3.8 s
Horizontal distance traveled by the raft in time t
d = v x t = 5.6 x 3.8 = 21.28 m
This is a question that would have literally have taken two seconds to look up on google but the answer is 1.88 years.