Glossary
1D Motion
Movement of an object restricted to a single straight line, either horizontally or vertically.
Example:
A train moving along a straight track demonstrates 1D motion.
2D Motion
Movement of an object that occurs in two dimensions, typically involving both horizontal and vertical components simultaneously.
Example:
A thrown football follows a parabolic path, illustrating 2D motion.
Acceleration
The rate at which an object's velocity changes over time, which can involve a change in speed, direction, or both.
Example:
When a car speeds up, slows down, or turns a corner, it experiences acceleration.
Acceleration
The rate at which an object's velocity changes over time. It is a vector quantity, indicating how quickly and in what direction velocity is changing.
Example:
When a rocket launches, its increasing speed means it experiences significant upward acceleration.
Acceleration Vector
A vector that describes the rate of change of an object's velocity vector in two or three dimensions. Its components correspond to the acceleration along each axis.
Example:
When a satellite enters orbit, its acceleration vector is directed towards the center of the Earth, causing it to curve.
Acceleration due to Gravity (g)
The constant acceleration experienced by objects in free fall near Earth's surface, approximately 9.8 m/s² directed downward.
Example:
When you jump, the Earth pulls you down with an acceleration due to gravity.
Acceleration-Time Graph
A graph that plots an object's acceleration on the y-axis against time on the x-axis, where the area under the curve represents the change in velocity.
Example:
A constant positive value on an acceleration-time graph means the object is steadily speeding up.
Acceleration-time graph
A graph that plots an object's acceleration on the y-axis against time on the x-axis. The area under the curve represents the change in velocity.
Example:
If a car brakes suddenly, its acceleration-time graph would show a large negative value for a short duration.
Angled Launches
A specific type of projectile motion where an object is launched at an initial angle relative to the horizontal.
Example:
Kicking a soccer ball high into the air involves an angled launch.
Center of Mass
The unique point where the weighted average of all the mass of an object or system is located.
Example:
For a perfectly symmetrical object like a baseball, the center of mass is at its geometric center.
Displacement
The change in an object's position, measured as the straight-line distance and direction from the initial to the final point.
Example:
If you walk 5 meters east and then 5 meters west, your total displacement is zero, even though you walked 10 meters.
Displacement
The change in an object's position, measured as a straight line from the initial to the final position. It is a vector quantity, including 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.
Displacement-time graph
A graph that plots an object's displacement on the y-axis against time on the x-axis. The slope of this graph represents velocity.
Example:
A horizontal line on a displacement-time graph indicates that an object is at rest, as its position is not changing.
Distance
The total path length traveled by an object, regardless of its direction.
Example:
If you walk 5 meters east and then 5 meters west, the total distance you traveled is 10 meters.
Distance
The total length of the path traveled by an object. It is a scalar quantity.
Example:
If you run around a 400-meter track twice, the total distance you covered is 800 meters.
Frame of Reference
The perspective or coordinate system from which an observer describes and measures motion.
Example:
A passenger on a moving train sees a ball drop straight down, while an observer on the ground sees a parabolic path due to different frames of reference.
Free Fall
The motion of an object solely under the influence of gravity, neglecting air resistance.
Example:
A dropped apple is in free fall once it leaves your hand.
Kinematic Equations
A set of mathematical formulas that relate position, velocity, acceleration, and time for objects undergoing constant acceleration.
Example:
Using the kinematic equations, you can predict how far a car will travel before stopping if you know its initial speed and deceleration.
Kinematics
The branch of mechanics that describes the motion of points, objects, and groups of objects without considering the causes of motion.
Example:
Describing the path of a thrown baseball without analyzing the force from the pitcher's arm is an example of kinematics.
Kinematics
The branch of mechanics that describes the motion of points, objects, and groups of objects without reference to the causes of motion.
Example:
When analyzing the flight of a baseball, kinematics helps us determine its trajectory and landing spot without considering the force of the bat.
Maximum Height
The highest vertical position reached by a projectile during its trajectory.
Example:
A diver reaching the peak of their jump before descending illustrates their maximum height.
One-dimensional kinematics
The study of motion along a single straight line. Objects move only forward/backward or up/down.
Example:
Analyzing a train moving on a straight track or a ball dropped vertically is part of one-dimensional kinematics.
Position
An object's location in space relative to a defined origin or reference point.
Example:
If you're at x = 5 meters on a number line, your position is 5 meters from the origin.
Position
The location of an object relative to a chosen reference point or origin.
Example:
On a coordinate plane, the position of a satellite might be given as (x, y, z) relative to the center of the Earth.
Position Vector
A vector that describes the location of a point in space relative to an origin. It points from the origin to the object's position.
Example:
In a game, the location of a player on the field can be represented by a position vector from the center of the field.
Position-Time Graph
A graph that plots an object's position on the y-axis against time on the x-axis, where the slope represents velocity.
Example:
A straight, diagonal line on a position-time graph indicates constant velocity.
Projectile Motion
The motion of an object launched into the air that is subject only to the force of gravity, neglecting air resistance.
Example:
The flight of a basketball shot is a classic example of projectile motion.
Projectile Motion
The motion of an object thrown or projected into the air, subject only to the acceleration of gravity. It is a common application of two-dimensional kinematics.
Example:
Calculating the maximum height and range of a cannonball fired from a ship involves understanding projectile motion.
Range
The total horizontal distance covered by a projectile from its launch point to where it lands.
Example:
A cannonball's range is how far it travels horizontally before hitting the ground.
Resultant Vectors
The single vector that represents the combined effect or sum of two or more individual vectors.
Example:
Combining the horizontal and vertical displacement of a boat gives its overall resultant vector of displacement.
SUVAT
An acronym used as a mnemonic to remember the five key variables (Displacement, Initial Velocity, Final Velocity, Acceleration, Time) involved in the constant acceleration kinematic equations.
Example:
When solving a problem about a car braking, using the SUVAT equations helps you quickly identify which formula to use based on the known and unknown variables.
Scalar
A physical quantity that is fully described by its magnitude (size) only.
Example:
Your speed on a roller coaster is a scalar quantity, as it doesn't include direction.
Scalar Quantity
A physical quantity that has only magnitude and no direction.
Example:
Your mass, the temperature outside, and the amount of energy consumed by a light bulb are all examples of scalar quantities.
Speed
The rate at which an object covers distance, a scalar quantity that only indicates magnitude.
Example:
A car's speedometer measures its speed.
Speed
The rate at which an object covers distance. It is a scalar quantity, only indicating magnitude.
Example:
A cheetah can reach a top speed of about 70 mph, regardless of the direction it's running.
Time
A fundamental dimension in which events occur, measured in units like seconds. It is a scalar quantity.
Example:
The time it takes for a pendulum to complete one full swing is a crucial factor in its design.
Time of Flight
The total duration an object remains in the air from its launch until it lands, typically in projectile motion.
Example:
The time of flight for a golf ball is how long it stays airborne from the tee to landing.
Two-dimensional kinematics
The study of motion in a plane, typically involving independent motion along two perpendicular axes (e.g., x and y).
Example:
The flight of a thrown football, which moves both horizontally and vertically, is a classic problem in two-dimensional kinematics.
Uniform motion
Motion characterized by constant velocity, meaning both constant speed and constant direction. In this state, acceleration is zero.
Example:
A spaceship drifting through space far from any gravitational influence is an example of uniform motion.
Uniformly accelerated motion
Motion in which an object's acceleration remains constant over time. This results in a linear change in velocity.
Example:
An object in free fall near the Earth's surface experiences uniformly accelerated motion due to constant gravitational acceleration.
Vector
A physical quantity that has both magnitude (size) and direction.
Example:
The velocity of a rocket launching upwards is a vector because it specifies both speed and direction.
Vector Components
The perpendicular parts of a vector that lie along the coordinate axes (e.g., x and y axes), which can be used to analyze motion in multiple dimensions.
Example:
The initial velocity of a projectile can be broken down into its horizontal and vertical vector components.
Vector Quantity
A physical quantity that has both magnitude and direction.
Example:
When pushing a heavy box, the force you apply is a vector quantity because it has both a strength (magnitude) and a direction.
Velocity
The rate at which an object's position changes, including both its speed and direction.
Example:
A car moving at 60 km/h north has a specific velocity.
Velocity
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 mph north has a different velocity than a car traveling at 60 mph south, even though their speeds are the same.
Velocity Vector
A vector that describes an object's instantaneous speed and direction in two or three dimensions. Its components correspond to the velocity along each axis.
Example:
For a car turning a corner, its velocity vector is constantly changing direction, even if its speed remains constant.
Velocity-Time Graph
A graph that plots an object's velocity on the y-axis against time on the x-axis, where the slope represents acceleration and the area represents displacement.
Example:
A horizontal line on a velocity-time graph means constant velocity and zero acceleration.
Velocity-time graph
A graph that plots an object's velocity on the y-axis against time on the x-axis. The slope represents acceleration, and the area under the curve represents displacement.
Example:
A straight, sloped line on a velocity-time graph signifies constant acceleration, such as a car steadily speeding up.