The great roman poet, lucretius wrote, "things cannot be born from nothing, cannot when begottend brought back to nothing." this statement became an accepted theory as a result of the work of the chemist, lavoisier in the 18th century. this is the law of conservation of matter. similarly, the law of conservation of energy is an important law in physics. can you discuss the validity of the conservation of energy in terms of potential (gravitational or elastic) and kinetic energy by giving real-life applications

Explanation:

When a swing is at its maximum height, the potential energy, associated with the height, is maximum. At this point its speed is zero, so the kinetic energy is zero. As the swing descends, having less height, the potential energy decreases and the kinetic energy increases. When it passes through the position with the minimum height, the potential energy is minimal and the kinetic energy is maximum.

This is true in the ideal case, in which there is no friction due to air resistance.  When friction is taken into account, implies that the swing stops gradually, since its energy is converted into thermal energy

i think they are all correct

explanation:

they seem good

it's when something is going so fast it makes a loud noise, breaking the sound barrier, for example: a jet makes a loud noise, not only cause of the jet but because they reached a point where they went so fast that you can year the noise from various parts, kinda like a police car, lets say the car was going   so fast that you hear the siren of the cop car right next to you, but the car is probably a mile a way, it's cos the siren was next to you a few seconds if you understand me