Physics Fundamentals - Kinematics, Forces, Energy & Simple Machines

Vocabulary flashcards covering key terms and definitions from the lecture notes on physics basics, motion, forces, energy, and simple machines.

Physics

The study of the basic constituents of the natural world and their relationships (matter and energy).

Matter

One of the basic constituents of the natural world; the universe is made of matter and energy.

Energy

The capacity to do work; a property that must be transferred to perform work.

Classical Physics

Branch that emerged before the 20th century; studies the behavior of matter and energy at normal scales.

Modern Physics

Branch that emerged at the start of the 20th century; studies behavior under extreme conditions.

Kinematics

The study of motion of objects; a branch of Classical Physics focusing on motion without considering forces.

Motion

Change in position of an object with respect to time.

Distance

Total ground covered during motion; scalar; always ≥ 0; units include km, m, miles, feet.

Displacement

Overall change in position; vector; includes direction; straight-line; same units as distance.

Speed

Rate at which distance is covered; scalar; always positive; units include m/s, km/h.

Velocity

Rate of motion with a direction; vector; includes direction; units same as speed.

Scalar quantities

Quantities with magnitude only (no direction); e.g., energy, length, mass, speed, time, temperature.

Vector quantities

Quantities with both magnitude and direction; e.g., displacement, force, velocity, acceleration, momentum.

Distance vs Displacement

Distance is the total ground covered (scalar); Displacement is the straight-line change in position with direction (vector).

Constant speed

Motion where speed does not change.

Average speed

Total distance traveled divided by the total time.

Velocity (direction in problems)

In word problems, velocity includes a direction (e.g., east, north).

Acceleration

Rate of change of velocity per unit time; unit m/s^2; four types: positive, negative (deceleration), zero, uniform.

Positive acceleration

Moving with increasing speed.

Negative acceleration (deceleration)

Slowing down.

Zero acceleration

Moving at a constant speed.

Uniform acceleration

Acceleration that does not change during motion.

Law of Inertia

An object at rest stays at rest, or moves at constant velocity in a straight line, unless acted upon by a net external force.

Law of Interaction (Newton's Third Law)

When one object exerts a force on another, the second exerts an equal and opposite force.

Force

A push or pull acting on an object due to interaction with another object; can be contact or non-contact.

Contact forces

Forces arising from contact between objects; examples include push/pull, tension, compressive, weight, friction.

Push or Pull

Basic type of contact force.

Tension

Force exerted upward when an object is suspended.

Compressive force

Force from squeezing or compressing an object.

Weight

Force exerted by gravity on an object toward the center of the Earth.

Friction

Opposing force arising from contact between surfaces; resists motion.

Work

Product of force and displacement; done when a force moves an object; can be positive, negative, or zero.

Positive work

Force and displacement are in the same direction.

Negative work

Force opposite to the direction of displacement.

Zero work

Force perpendicular to the displacement.

Work and energy

Work is the change in energy.

Power

Rate of doing work; work divided by time; units: watts (W) or J/s.

Energy (mechanical)

Capacity to do work; includes kinetic and potential energy.

Kinetic Energy (KE)

Energy of motion; KE = 1/2 m v^2.

Potential Energy (GPE)

Gravitational potential energy; GPE = m g h.

Momentum

A measure of tendency to continue in motion; p = m v; units kg·m/s.

Collision types

Elastic: kinetic energy conserved; Inelastic: KE not conserved; Perfectly inelastic: objects stick; momentum conserved, KE not.

Simple Machines

Tools that reduce the effort needed to do work; simple machines have few parts; complex machines combine several simple machines.

Tool

A mechanical device intended to make work easier.

Machine

A device that uses energy to do work; reduces the force needed but may require more distance.

Inclined Plane

Used to raise or lower heavy objects.

Wedge

Two inclined planes meeting; cuts things apart; narrower wedge eases splitting.

Screw

Inclined plane wrapped around a rod; threads drive the screw into material; holds pieces together.

Lever

A bar resting on a fulcrum; pivots to move heavy objects.

Wheel and Axle

Wheel turns the axle; larger distance moved with less force; reduces friction.

Gear

Teeth on a wheel that transfer force and can change speed or force.

Pulley

A wheel with a rope system to lift loads or reduce required force.

Scissor

Cutting tool with blades that pivot on a fulcrum; handles act as levers.