Which statement most accurately describes the second law of thermodynamics?
1 answer:
Answer:
Energy cannot be changed from one form to another without a loss of usable energy
Explanation:
Second law of thermodynamics states that the total entropy or the randomness of the system remains constant over time. It also states that the net entropy will remain the same or it will increase.
Entropy of a system is given by heat absorbed divided by temperature. It is given by :
So, the correct option is (A) "Energy cannot be changed from one form to another without a loss of usable energy".
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Answer:
work done is -2.8 × 10⁻⁶ J
Explanation:
Given the data in the question;
mass of the pendulum m = 6 kg
Length of core = 1.7 m
Now, case1, mass is pulled aside a small distance of 7.6 cm and released from rest. so let θ₁ be the angle made by mass with vertical axis.
so, θ₁ = ( 7.6 × 10⁻² m / 1.7 m ) = 0.045 rad
In case2, mass is pulled aside a small distance of 8 cm and released from rest. so let θ₁ be the angle made by mass with vertical axis.
so, θ₂ = ( 8 × 10⁻² m / 1.7 m ) = 0.047 rad.
Now, the required work done will be;
W = -cosθ
W = 6 × 9.8 × 1.7 × [ cos( 0.047 ) - cos( 0.045 ) ]
W = 6 × 9.8 × 1.7 × [ -2.8 × 10⁻⁸ ]
W = -2.8 × 10⁻⁶ J
Therefore, work done is -2.8 × 10⁻⁶ J