Glossary
Acceleration (a)
The rate at which an object's velocity changes over time. It is a vector quantity, indicating a change in speed, direction, or both.
Example:
When a roller coaster speeds up as it goes down a hill, it experiences positive acceleration.
Conservation of Charge
A fundamental principle stating that the total electric charge in an isolated system remains constant. Charge cannot be created or destroyed, only transferred.
Example:
If a neutral object gains electrons from another object, the total charge of the two-object system remains zero, demonstrating the conservation of charge.
Displacement (Δx)
The change in an object's position, measured as a straight line from the initial to the final point. It is a vector quantity, meaning it has both magnitude and direction.
Example:
If you walk 5 meters east and then 5 meters west, your total distance traveled is 10 meters, but your displacement is 0 meters.
Electric Charge (q)
A fundamental property of matter that causes it to experience a force when placed in an electromagnetic field. It can be positive or negative.
Example:
When you rub a balloon on your hair, you transfer electric charge, causing the balloon to stick to a wall.
Electron
A subatomic particle that orbits the nucleus of an atom and carries a single negative elementary electric charge.
Example:
Static electricity often results from the transfer of electrons between surfaces.
Electrostatic Force (Fe)
The attractive or repulsive force between two charged objects. Like charges repel, and opposite charges attract.
Example:
The invisible push that makes two positively charged balloons move away from each other is the electrostatic force.
Horizontal Motion
The movement of a projectile along the x-axis, characterized by constant velocity (zero acceleration) when air resistance is neglected.
Example:
When a cannonball is fired, its forward movement across the ground is its horizontal motion, which remains steady if there's no air resistance.
Kinematic Equations
A set of mathematical equations used to describe the motion of objects under constant acceleration. They relate displacement, initial velocity, final velocity, acceleration, and time.
Example:
To predict how far a dropped ball will fall in a certain amount of time, you would use the kinematic equations.
Neutron
A subatomic particle found in the nucleus of an atom that has no net electric charge.
Example:
Isotopes of an element differ in the number of neutrons in their nuclei.
Newton's 1st Law (Inertia)
States that an object at rest stays at rest, and an object in motion stays in motion with the same velocity unless acted upon by a net external force.
Example:
When a car suddenly brakes, your body continues to move forward due to Newton's 1st Law.
Newton's 2nd Law (F=ma)
States that the acceleration of an object is directly proportional to the net force acting on it and inversely proportional to its mass. It is expressed by the equation F = ma.
Example:
Pushing a small toy car with the same force as a large truck will cause the toy car to have much greater acceleration, as described by Newton's 2nd Law.
Newton's 3rd Law
States that for every action, there is an equal and opposite reaction. Forces always occur in pairs.
Example:
When a rocket expels hot gas downward, the gas exerts an equal and opposite force upward on the rocket, propelling it, which is an application of Newton's 3rd Law.
Proton
A subatomic particle found in the nucleus of an atom that carries a single positive elementary electric charge.
Example:
The number of protons in an atom's nucleus determines its atomic number and thus its element.
Velocity (v)
The rate at which an object's displacement changes over time. It is a vector quantity, indicating both speed and direction.
Example:
A car traveling at 60 km/h north has a different velocity than a car traveling at 60 km/h south.
Vertical Motion
The movement of a projectile along the y-axis, characterized by constant acceleration due to gravity (g = 9.8 m/s² downward).
Example:
The upward and downward path of a basketball shot is its vertical motion, constantly affected by gravity.