Analysis about the First and Second Law of Thermodynamics

AI Thread Summary
The discussion focuses on the First and Second Laws of Thermodynamics, addressing specific scenarios. The electric car design described violates the First Law, as it suggests perpetual motion by implying that energy can be created from nothing through regenerative braking. Regarding the Second Law, the operation of a refrigerator does not violate it, as it requires external energy to maintain the temperature difference between the inside and outside. The engineer's firing likely relates to a failure to adhere to these thermodynamic principles in the roller coaster design. Understanding these laws is crucial for evaluating energy systems and mechanical designs.
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Hi guys! Can anyone please help me with these questions about the 1st and 2nd Law of Thermodynamics?

First Law of Thermodynamics

1. An inventor has designed an electric car in the following manner. Batteries in the car power an electric motor that drives the vehicle. When the car coasts downhill or comes to a stop and its motor is not needed, the kinetic energy of the car is converted to rotational energy and is used to turn an electric generator. The generator provides electricity to charge the batteries. According to the inventor, a great deal of energy is saved in this manner, and the car can travel much longer on a single battery charger than a conventional electric car can. Will this machine work? Why or why not?

Second Law of Thermodynamics

1. A refrigerator causes a separation of hot and cold; cold air is maintained inside the unit while the kitchen remains warm. Is this separation a violation of the second law?

2. An engineer designed and built the roller coaster. He was fired. Why?
 
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Please post some attempts at the problems, before we can help you.
 
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Thread 'Collision of a bullet on a rod-string system: query'

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Thread 'A cylinder connected to a hanged mass'

Thread 'A cylinder connected to a hanged mass'

Let's declare that for the cylinder, mass = M = 10 kg Radius = R = 4 m For the wall and the floor, Friction coeff = ##\mu## = 0.5 For the hanging mass, mass = m = 11 kg First, we divide the force according to their respective plane (x and y thing, correct me if I'm wrong) and according to which, cylinder or the hanging mass, they're working on. Force on the hanging mass $$mg - T = ma$$ Force(Cylinder) on y $$N_f + f_w - Mg = 0$$ Force(Cylinder) on x $$T + f_f - N_w = Ma$$ There's also...
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