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

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.