3C Energy forms and transfers Flashcards
Learn about energy forms, transfer methods, and conservation laws. Study simple machines and their mechanical advantages.
What is energy?
The ability to do work, involving movement.
List the forms of energy.
- Thermal
- Kinetic
- Light
- Sound
- Chemical
- Electrical
- Mechanical
- Radiant
- Nuclear
- Gravitational
Each form of energy can transform into another form, adhering to the law of conservation of energy.
What are the two main categories of energy?
- Kinetic energy
- Potential energy
What is kinetic energy?
The energy of movement or motion, calculated as half the mass of an object multiplied by its velocity squared.
What is the equation for kinetic energy?
KE = 0.5 x mv²
Where:
KE represents the kinetic energy
m represents the mass
v represents the velocity
This equation shows that kinetic energy increases with the square of the velocity.
What are some examples of kinetic energy?
- A ball rolling down a hill.
- A person running a marathon.
- Cars driving.
- Water flowing in a river.
Any object in motion has kinetic energy.
Define potential energy.
Stored energy that has the potential to do work, calculated as mass multiplied by the gravity constant and height.
What is the equation for potential energy?
PE = mass x gravity constant x height
Potential energy depends on the object’s mass, height, and the gravitational field.
Provide an example of potential energy.
- A rock at the edge of a cliff.
- A car stopped at the top of a hill.
- Water behind a dam.
What is the main difference between kinetic and potential energy?
- Kinetic energy involves motion.
- Potential energy is stored and not moving.
The two forms of energy are interconvertible.
Can kinetic energy be transferred? Give an example.
Yes, an example is bowling where energy is transferred from the bowler to the ball, which then transfers energy to the pins.
Energy transfer can occur through collisions or direct contact.
Can potential energy be converted to kinetic energy? Provide an example.
Yes, an example is when an apple falls from a tree, its potential energy is converted to kinetic energy as it moves.
The conversion of potential to kinetic energy is influenced by the gravitational force.
Can kinetic energy be converted to potential energy? Provide an example.
Yes, when a ball is thrown into the air, its kinetic energy converts to potential energy at the highest point of its arc.
At the peak, the ball has maximum potential energy and minimum kinetic energy.
How does the law of conservation of energy relate to kinetic and potential energy?
Energy cannot be created or destroyed but can be transformed from one form to another, such as from kinetic to potential energy and vice versa.
Total energy in an isolated system remains constant.
What happens to kinetic energy when a moving object stops?
It is converted into potential energy.
Friction often converts kinetic energy into thermal energy.
What is chemical potential energy?
The energy stored in chemical bonds, released when the bonds are broken, such as in an explosion.
This energy is crucial for biological processes and fuel combustion.
Give an example of chemical potential energy.
- Dynamite has chemical potential energy that is released in a massive explosion when lit.
- Batteries also store chemical energy that is converted into electrical energy.
How is kinetic energy relative to surroundings?
It depends on the velocity of an object relative to its surroundings, such as a child riding a bike down a hill.
Why is potential energy considered “stored” energy?
Because it represents the capacity to do work due to an object’s position or state, not due to motion.
Can energy be created or destroyed?
No.
According to the law of conservation of energy, it can only be transformed from one type to another.
This principle is fundamental to all physical processes.
What are the three methods of heat transfer?
- Conduction
- Convection
- Radiation
Each method involves different mechanisms of heat movement.
Describe how energy transfer occurs in a windmill.
Wind energy is converted into mechanical energy by the windmill’s blades, which then generates electrical energy.
The mechanical energy turns a generator to produce electricity.
How does a solar panel transfer energy?
It converts solar radiation into electrical energy through the excitation of particles within the solar cell.
Photovoltaic cells are key components in solar panels that facilitate this conversion.
What happens to the kinetic and potential energy of a ball at the peak of its throw?
The ball’s kinetic energy is at its minimum, and its potential energy is at its maximum.
How does energy transfer in the process of photosynthesis?
Solar energy is converted into chemical energy in plants during photosynthesis.
How many types of simple machines are there?
Six
- Inclined planes
- Levers
- Wheel and axles
- Pulleys
- Wedge
- Screws
Give an example of a lever and explain how it works.
A seesaw - it works by balancing a beam on a fulcrum, where the effort arm’s length can be adjusted to lift heavier objects with less force.
What is an inclined plane and how does it work?
It is a sloped surface that reduces the force needed to lift objects by changing the direction of the force applied.
Examples of inclined planes include stair ramps, hills, truck ramps, and spiral scaffolding.
Describe a wedge and its function.
It’s a device that is thick at one end and tapers to a thin edge at the other, used to split objects apart by converting a force applied to its blunt end into forces perpendicular to its inclined surfaces.
Examples include axes and knives.
Explain the wheel and axle as a simple machine.
It consists of a large circular wheel attached to a smaller axle; turning the wheel turns the axle, allowing objects to be lifted with less force over a greater distance.
This system reduces the friction involved in moving objects.
What is a fulcrum in the context of a lever?
The pivot point on which a lever balances and rotates to lift or move an object.
The position of the fulcrum determines the mechanical advantage of the lever.
How does the length of the effort arm affect the force needed in a lever?
The longer the effort arm relative to the resistance arm, the less force is needed to lift a heavy object.
This is due to the increased mechanical advantage provided by a longer effort arm.
