Very Short Question and Answers - Law of Conservation of Energy

Yes, energy can be converted from one form to another.

Green plants produce food through the process of photosynthesis, utilizing sunlight, carbon dioxide, and water.

Green plants get their energy primarily from sunlight.

Air moves due to differences in temperature and pressure which create wind.

Fuels such as coal and petroleum are formed from the remains of ancient plants and animals that have undergone heat and pressure underground over millions of years.

In the water cycle, energy from the sun causes evaporation, which is then followed by condensation and precipitation, representing conversions between thermal energy, potential energy, and kinetic energy.

The law of conservation of energy states that energy can neither be created nor destroyed; it can only be transformed from one form to another.

The total energy of a system remains unchanged during or after energy transformation.

Potential energy is the energy possessed by an object due to its position or height.

Kinetic energy is the energy possessed by an object due to its motion.

The formula for potential energy is Ep = mgh, where m is mass, g is gravitational acceleration, and h is height.

The formula for kinetic energy is Ek = 1/2 mv², where m is mass and v is velocity.

As an object falls, its potential energy decreases while its kinetic energy increases.

Total mechanical energy is the sum of potential energy and kinetic energy of an object.

Air resistance affects the energy transformation by converting some mechanical energy into thermal energy, which is generally ignored in ideal calculations.

Potential energy can be calculated using the formula Ep = mgh. For a mass of 20 kg at a height of 4 m and g as 10 m/s², Ep = 20 kg * 10 m/s² * 4 m = 800 J.

Kinetic energy can be calculated using the formula Ek = 1/2 mv². If the object falls from 4 m, you first find its velocity v just before hitting the ground using v² = 2gh.

The total energy at the start is entirely potential energy, which is 800 J if the object has 20 kg mass.

No, the total energy remains constant throughout the free fall, as potential energy converts into kinetic energy.

Human activities such as cooking (thermal energy to chemical energy) and driving a car (chemical energy in fuel to kinetic energy) demonstrate energy conversion.