# VOCABULARY GUIDE

CONDUCTOR
A type of material in which electric charges are easy to move around. Wires, for example, are made of conducting material

CONSERVATION OF ENERGY
Explains that energy can change from one form to another, but the total amount of energy always stays the same.

DISTANCE
Difference in position, typically measured from the origin. When it comes to traveling in multiple (different) directions, however, a distinction needs to be made between the TOTAL DISTANCE TRAVELED vs TOTAL DISPLACEMENT. Total distance traveled is the sum of all the distances you travel, regardless of the direction; in other words, it's what the odometer on your car is measuring. Total displacement is the difference in position between where you start and where you end up. For example, if you travel 2 miles to the nearest grocery store, and then back home, then the total distance traveled is 4 miles, but the total displacement is zero, because you're back to where you started.

ELECTRIC CHARGE
A property of an object that determines the strength of the electrical interaction with other charged objects. There are two kinds of charges: POSITIVE and NEGATIVE. A positive charge is characterized by electric field lines that point AWAY from the charge, whereas a negative charge is characterized by electric field lines that point TOWARD the charge.

ELECTRIC CURRENT
A flow of electric charges. More specifically, the amount of charges passing through a point every second. The direction of the flow in a typical electric circuit is DEFINED to be from the HIGHER VOLTAGE end of the battery to the LOWER VOLTAGE end, but the charge carriers are actually electrons, so the charges actually flow from lower potential to higher potential

FORCE - ELECTRICAL
The force that occurs due to the interaction between charges. This force can be either attractive or repulsive, depending on the sign of the charges; like charges will repel each other, while opposite charges will attract.

FORCE - GRAVITATIONAL
The force that pulls any object on earth towards the center earth. Generally speaking, gravitational force is the force that occurs due to the interaction between two masses. In the case of an object falling to the ground, the object itself is considered to be one mass, and the earth the other mass. Gravitational force on earth is also often referred to as "weight."

FRICTION
A force that resists the motion between two touching bodies

HEAT
The transfer of Kinetic Energy from one body to another because of a difference in temperature.

HEIGHT
Difference in elevation, measured some pre-determined zero point. This zero point is typically the ground, but can be arbitrarily set anywhere to simplify calculation.

KINETIC ENERGY
The energy that an object has due to its speed. The kinetic energy of an object is proportional to the square of its speed, so doubling the speed will increase the kinetic energy by four times as much (fact stated in typical DMV books)

POTENTIAL ENERGY - ELECTRICAL
The energy that a charged object has when placed inside an electric field, either an external field or one created by another charged object.

POTENTIAL ENERGY - GRAVITATIONAL
The energy that an object with a mass has when placed at a certain height from some zero reference point

RESISTANCE
Things that get in the way of the flow of charges in a conductor. In other words, resistance slows down current.

VOLTAGE / POTENTIAL DIFFERENCE
The quantity that measures the difference in electric potential; it is essentially just another way of saying "Potential Difference" (NOT potential energy difference). Voltage is created when there is a separation of charges. Because it takes Work to separate charges, we can say that there is some energy "stored" inside this separation of charges. In fact, when a charged particle goes through a potential difference, the charged particle gains potential energy.

WORK
Unlike the term "work" used on a daily basis, in Physics, Work is a form of energy (measured in Joules). Work is usually associated with the change in energy of an object, be it Potential or Kinetic. For example: Work is done when lifting a chunk of rock off the ground to a certain height, because the rock's Potential Energy changes. Work is also done with a car slows done or accelerates, because the car's Kinetic Energy changes.