Chapter 9.4 - How is Energy Conserved?

Question 1

How is Energy conserved?

Answer 1

Energy is conserved according to the law of conservation of energy, which states that energy cannot be created or destroyed, only transformed from one form to another. In other words, the total amount of energy in a system remains constant over time, although it can change form.

For example, when a ball is dropped from a height, its potential energy (energy stored in an object due to its position) decreases as it falls, but its kinetic energy (energy due to the motion of an object) increases. The total energy of the ball remains constant, because the decrease in potential energy is equal to the increase in kinetic energy.

Similarly, when a car collides with a wall, the kinetic energy of the car is transformed into other forms of energy, such as thermal energy (energy due to the motion of particles) and sound energy. The total energy of the car and the wall remains constant, although it may change form.

In general, energy is conserved in any system that is isolated from its surroundings, meaning that it does not exchange energy with its environment. Energy can be transferred from one object to another or from one form to another, but the total amount of energy in the system remains constant.

In short, energy is conserved according to the law of conservation of energy, which states that the total amount of energy in a system remains constant over time, although it can change form.

Question 2

Name an example of:

1) Electrical energy to Kinetic Energy
2) Light Energy to Potential Energy
3) Potential Energy to Light Energy

Answer 2

1) Tesla Electric Car
2) Photosyntesis in plants
3) Light bulb

Question 3

What is the si unit for energy?

Answer 3

Joule (J)