Answer:
a. -4.166 J/K
b. 8.37 J/K
c. 4.21 J/K
d. entropy always increases.
Explanation:
Given :
Temperature at hot reservoir , 
= 720 K
Temperature at cold reservoir , 
= 358 K
Transfer of heat, dQ = 3.00 kJ = 3000 J
(a). In the hot reservoir, the change of entropy is given by:
(the negative sign shows the loss of heat)
= -4.166 J/K
(b) In the cold reservoir, the change of entropy is given by:
= 8.37 J/K
(c). The entropy change in the universe is given by:
= -4.16+8.37
= 4.21 J/K
(d). According to the concept of entropy, the entropy of the universe is always increasing and never decreasing for an irreversible process. If the entropy of universe decreases, it violates the laws of thermodynamics. Hence, in part (c), the result have to be positive.
Answer:
A) continue to move to the right, with its speed increasing with time.
Explanation:
As long as force is positive , even when it is decreasing , it will create positive increase in velocity . Hence the body will keep moving with increasing velocity towards the right . The moment the force becomes zero on continuously decreasing , the increase in velocity stops and the body will be moving with the last velocity uniformly towards right . When the force acting on it becomes negative , even then the body will keep on going to the right till negative force makes its velocity zero . D uring this period , the body will keep moving towards right with decreasing velocity .
Hence in the present case A , is the right choice.
Answer:
1.635×10^-3m
Explanation:
Young modulus is the ratio of the tensile stress of a material to its tensile strain.
Young modulus = Tensile stress/tensile strain
Tensile stress = Force/Area
Given force = 130N
Area = Πr² = Π×(1.55×10^-3)²
Area = 4.87×10^-6m²
Tensile stress = 130/4.87×10^-6 = 8.39×10^7N/m²
Tensile strain = extension/original length
Tensile strain = e/3.9
Substituting in the young modulus formula given young modulus to be 2×10¹¹N/m²
2×10¹¹N/m² = 8.39×10^7/{e/3.9)}
2×10¹¹ = (8.39×10^7×3.9)/e
2×10¹¹e = 3.27×10^8
e = 3.27×10^8/2×10¹¹
e = 1.635×10^-3m
The stretch of the steel wire will be
1.635×10^-3m
Answer:
the correct answer is 273.2 k
Answer:
500000000
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