FORMS OF ENERGY
What is the energy of position or stored energy called?
Potential Energy
Define energy conversion.
The change one form of energy into another
Define force.
Any push or pull that changes the motion or shape of an object
What is the definition of a machine?
A device that makes work SEEM easier by changing the size OR direction of a force
What does the Law of Conservation of Energy state?
Energy cannot be created or destroyed; it can only be transferred from one type of energy to another
Which form of energy is produced when nuclei of atoms are joined or split?
Nuclear Energy
Provide an example of energy conversion in daily life.
The Sun transforms nuclear energy into heat and light energy.
Our bodies convert chemical energy in our food into mechanical energy for us to move.
An electric fan transforms electrical energy into kinetic energy.
What is the force that opposes motion between two surfaces that are touching called?
Friction
Explain the concept of mechanical advantage.
MA = how many times the machine multiplies the force
MA = output force ÷ input force (weight ÷ effort)
The larger the MA, the easier the machine makes the work SEEM
Give an example of the Law of Conservation of Energy in action.
Electricity passes through a light bulb some of the electrical energy is converted to light energy and heat energy
School bus: chemical energy (gasoline) mechanical energy that turns wheel on bus with heat energy and sound energy as waste energy
How is thermal energy defined and what does it depend on?
Molecular movement of matter. The higher the temp, the faster the molecules are moving (kinetic energy) and the greater the thermal energy
What is the unit of measurement for energy and its symbol?
Joules (J)
How does friction change with the roughness of the surfaces in contact?
The rougher the surface, the higher the friction.
Define input force and output force in the context of machines.
The force you exert on the machine is called the input force.
The force the machine exerts on an object is
called the output force.
Finding the ratio of output force to input force
gives you the mechanical advantage of a machine.
How do energy resources help humans do useful work?
Energy resources are natural resources that can be converted by humans into other forms of energy in order to do useful work
Define electrical energy.
The movement of electrons (electricity)
When energy is converted from one form to another, what is the principal concept that remains constant?
Whether energy is converted, transferred, or transformed the amount of energy remains the same (constant).
What role do lubricants play in reducing friction?
Lubricants create a thin layer that prevents moving surfaces from directly rubbing against each other
What is it when a force causes an object to move a distance in the same direction as the force called?
Work is done when a force causes an object to move a distance in the same direction as the force
Explain the difference between renewable and nonrenewable resources.
Nonrenewable resources cannot be replaced or take thousands/millions of years to replace because they formed from remains of plants/animals that lived millions of years ago
Renewable resources are materials that can be replenished by nature within a relatively short time span
Explain what chemical energy is and provide an example.
Energy stored in certain substances because of what its chemical makeup is
Explain the Law of Conservation of Energy
Energy cannot be created or destroyed; it can only be transferred from one type of energy to another
Explain how the mass of objects influences friction between them.
More massive objects have greater force (more weight) = greater friction
Why can the work output never be greater than work input in a machine?
Work output can never be greater than work input.
In all machines, some work is wasted due to friction.
Mention one nonrenewable and one renewable energy resource, and explain their differences.
Nonrenewable resource - Fossil fuels (coal, petroleum (oil), and natural gas).
Renewable resource - Hydroelectric, Nuclear, Solar, Wind, Thermal, Biomatter (plant and animal decay/waste)
The issue is waste and the procedures (external energy) needed to cause the transfer/tranformation of energy