Physics science test 2

Force

A push or a pull acting on an object, measured in Newtons (N).

Net Force

The overall combined force acting on an object after all individual forces are added together.

Balanced Forces

Forces acting on an object that combine to produce a net force of zero, resulting in no change in motion.

Unbalanced Forces

Forces that produce a non-zero net force, causing an object to accelerate or change direction.

Four Fundamental Forces

1. Strong nuclear force, 2. Electromagnetic force, 3. Weak nuclear force, 4. Gravitational force.

Friction

A contact force that opposes the relative motion of two surfaces in contact.

Static Friction

The friction force acting on stationary objects that prevents them from starting to move.

Sliding (Kinetic) Friction

The friction force opposing the motion of an object as it slides across a surface.

Rolling Friction

The friction force acting on rolling objects, which is significantly weaker than sliding friction.

Fluid Friction

The resistive force opposing motion through a liquid or gas.

Air Resistance (Drag)

Fluid friction acting on an object moving through the air; depends on speed, surface area (size), and shape.

Terminal Velocity

The maximum constant velocity reached by a falling object when upward air resistance equals downward gravity.

Gravity

An attractive force that acts between any two masses in the universe.

Law of Universal Gravitation

Every mass attracts every other mass; gravitational force increases with mass and decreases with distance squared.

Acceleration Due to Gravity (g)

The rate of free-fall acceleration on Earth, equal to 9.8 m/s² (or approximately 10 m/s²).

Mass

The measure of the amount of matter in an object; a scalar quantity measured in kilograms (kg) that does not change with location.

Weight

The measure of the gravitational pull acting on an object's mass; a vector quantity measured in Newtons (N).

Weight Formula

W = m · g, where W is weight in Newtons (N), m is mass in kg, and g is gravitational acceleration (9.8 m/s²).

Projectile Motion

The curved path followed by an object thrown or launched, caused by a constant horizontal velocity and downward gravitational acceleration.

Centripetal Force

A center-directed force that keeps an object moving in a circular path, acting perpendicular to the object's velocity.

Newton's Second Law Formula

F_net = m · a (or a = F_net / m), where force is in Newtons (N), mass is in kilograms (kg), and acceleration is in m/s².

Newton's Third Law

For every action force, there is an equal magnitude and opposite direction reaction force.

Momentum

A measure of how difficult it is to stop a moving object; calculated as mass times velocity.

Momentum Formula

p = m · v, where p is momentum in kg·m/s, m is mass in kg, and v is velocity in m/s.

Law of Conservation of Momentum

In a closed, isolated system, the total momentum before an interaction or collision equals the total momentum after.