Energy and Power
What unit do we use to measure energy?
Joules
What is work?
Work is force exerted on an object that causes the object to move some distance
What is temperature?
The temperature of an object is the measure of the average kinetic energy of the particles that make up that object.
What are AC and DC?
Alternating current and direct current.
What is gravitational potential energy?
Anything that can fall has stored energy called gravitational potential energy.
What are the 2 components of mechanical energy?
Mechanical energy is the sum of the kinetic energy and potential energy of the objects in a system.
What is a machine?
A machine makes work easier by changing the amount of force, the distance covered or by changing the direction of the force.
What is convection?
Convection is the transfer of thermal energy in a fluid by the movements of warmer and cooler fluid.
What is a magnetic field?
A magnetic field is a region of space that surrounds a magnet and exerts a force on other magnets and objects made of magnetic materials.
What is mechanical advantage?
A machine’s mechanical advantage is the number of times a force exerted on a machine is multiplied.
What is power?
The rate at which energy is converted is the object’s power.
What is a complex machine? Give an example
Two or more simple machines work together to form a complex machine.
What happens to the thermal energy as the temperature increases?
When the temperature of an object increases, the average kinetic energy of the particles that compose the object increases.
What is electromagnetism?
The interaction between electric charges and magnets is called electromagnetism.
What kind of energy do we use in our bodies? What do we use to measure this energy?
Chemical potential energy is used to fuel the processes that keep you alive. Calorie (C)
Name four different types of energy.
mechanical, electrical, chemical, and radiant.
What are the six kinds of simple machines?
Inclined plane, wedge, screw, lever, wheel and axle, and a pulley.
What is specific heat?
Specific Heat is the amount of heat that is needed to raise the temperature of 1 kg of a substance by 1°C
What are the two kinds of circuits? Describe them.
A series circuit is an electric circuit with only one branch. Series circuits are used in flashlights.
Parallel circuits contain two or more branches for current. Devices on each branch can be turned on or off separately.
What is heat? What unit do we use to measure heat?
Heat is thermal energy that is transferred from something at a higher temperature to something at a lower temperature. It is measured in joules.
What is the equation for power? What does each letter represent in this equation? What units do we use to measure power?
P=E/T
Power is measured in watts with 1 watt equaling 1 joule per second.
Describe each class of lever.
1. The input & output forces are in opposite directions. The fulcrum is between the input & output forces.
2. The input & output forces are in the same direction. Input force is farther away from the fulcrum than the output force.
3. The input & output forces are in the same direction. The input force is closer to the fulcrum than the output force
What is the equation for specific heat? What does each letter represent in this equation? What units do we use to measure specific heat?
Q=m(Tf-Ti)C
Change in thermal energy = mass * change in temperature * specific heat
Joules
What is an electromagnet?
An electromagnet is a temporary magnet created when there is a current in a wire coil. Often, the current-carrying coil is wrapped around an iron core
What is the equation for kinetic energy? What does each letter represent in this equation?
KE = 1/2 m * v^2