Answer:
ΔS total ≥ 0 (ΔS total = 0 if the process is carried out reversibly in the surroundings)
Explanation:
Assuming that the entropy change in the aluminium bar is due to heat exchange with the surroundings ( the lake) , then the entropy change of the aluminium bar is, according to the second law of thermodynamics, :
ΔS al ≥ ∫dQ/T
if the heat transfer is carried out reversibly
ΔS al =∫dQ/T
in the surroundings
ΔS surr ≥ -∫dQ/T = -ΔS al → ΔS surr ≥ -ΔS al = - (-1238 J/K) = 1238 J/K
the total entropy change will be
ΔS total = ΔS al + ΔS surr
ΔS total ≥ ΔS al + (-ΔS al) =
ΔS total ≥ 0
the total entropy change will be ΔS total = 0 if the process is carried out reversibly in the surroundings
Answer: A) 
Explanation:
The equation for the moment of inertia 
of a sphere is:
(1)
Where:
is the moment of inertia of the planet (assumed with the shape of a sphere)
is the mass of the planet
is the radius of the planet
Isolating from (1):
(2)
Solving:
(3)
Finally:
Therefore, the correct option is A.
Answer:a) 34.5 N; b) 24.5 N; c) 10 N; d) 1J
Explanation: In order to solve this problem we have to used the second Newton law given by:
∑F= m*a
F-f=m*a where f is the friction force (uk*Normal), from this we have
F= m*a+f=5 Kg*2 m/s^2+0.5*5Kg*9.8 m/s^2= 34.5 N
then f=uk*N=0.5*5Kg*9.8 m/s^2= 24.5N
the net Force = (34.5-24.5)N= 10 N
Finally the work done by the net force is equal to kinetic energy change so
W=∫Force net*dr= 10 N* 0.1 m= 1J
The answers is
D. The acid creates cracks in the rocks, which
allow air to circulate through the rock,
causing it to weather
The work done is by the centripetal force on mass m during an angular displacement of 2π revolutions mv²2π /r J
Centripetal force - a force acts on an moving object in circular path.
the centripetal force is given by
F= mv²/r (equation1)
Work done is given by
W = Fd (equation 2)
d = 2π
work is done by the centripetal force on mass m during an angular displacement of 2π revolutions is given by:
to calculate work done using equation 1 in 2 we get
W = mv² d/r
W = mv² × 2π /r J
The work done is by the centripetal force on mass m during an angular displacement of 2π revolutions mv²2π /r J
To know more about centripetal force :
brainly.com/question/13031430
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