Inertia
Resistance to change in the state of motion; objects at rest stay at rest and objects in motion stay in motion unless acted on by a force.
Net Force
The combination of all forces acting on an object, resulting in a change in its state of motion.
Equilibrium Rule
The state of no change; the vector sum of forces acting on a non-accelerating object equals zero (ΣF = 0).
Support Force
The force that supports an object on a surface against gravity, equivalent in magnitude and opposite in direction to the gravitational force.
Friction
The resistive force that opposes the motion of an object through a fluid or past another object.
Speed
The distance covered per unit of travel time.
Velocity
Speed plus the direction of motion.
Acceleration
The rate at which velocity changes over time; can be a change in magnitude, direction, or both.
Mass
A measure of the amount of matter in an object, which is also a measure of its inertia.
Weight
The force exerted on an object due to gravity, proportional to its mass.
Free Fall
The condition of falling under the influence of gravity alone, without air resistance.
Kilogram
The standard unit of measurement for mass, equivalent to the mass of 1 liter of water at 4°C.
Resultant vector
The single vector that results from the combination of two or more vectors.
Dynamic Equilibrium
A state in which an object moves at a constant velocity when forces cancel to zero.
Air Resistance
The force of friction acting on an object due to its motion through air.
Formula for Speed
Speed = Distance / Time
Units of Speed
Commonly measured in meters per second (m/s) or kilometers per hour (km/h).
Average Speed
Total distance traveled divided by total time taken.
Instantaneous Speed
The speed of an object at a specific moment in time.
Speed vs Velocity
Speed is a scalar quantity; velocity is a vector quantity that includes direction.
Constant Speed
When an object covers equal distances in equal intervals of time.
Variable Speed
When the speed of an object changes over time.
Speed and Acceleration
Acceleration is the rate of change of speed over time.