Answer:
I think it's A but I'm not sure
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".
Mass of first car = Initial mass (Mi) = 2 kg
Initial velocity (Vi) = 2 m/s
Mass of both cars together = Final mass (Mf) = 2 + 3 kg = 5 kg
Final Velocity (Vf) = ?
Applying law of conservation of momentum,
Mi x Vi = Mf x Vf
2 x 2 = 5 x Vf
Vf = 4/5 = 0.8 m/s