Forces and Energy - Lecture Notes Review

A set of practice flashcards covering key concepts from force, motion, energy, and related topics described in the notes.

What happens to the acceleration of a falling object as air resistance increases?

It eventually stops accelerating and reaches terminal velocity when air resistance balances gravity.

What is terminal velocity?

The constant speed achieved by a falling object when drag force equals gravitational force.

Newton's Third Law

For every action there is an equal and opposite reaction.

Conservation of Energy

Energy cannot be created or destroyed; it can be transferred or transformed.

Mechanical energy includes

Kinetic energy and potential energy.

Kinetic energy depends on

Mass and speed (KE = 1/2 m v^2).

Potential energy is based on

The shape and position of an object.

Thermal energy

Total kinetic energy of particles; increases with more particles and higher kinetic energy.

What is a force?

A push or pull on an object that can start or stop motion or change its motion.

Unbalanced forces

Net force not zero; causes a change in motion.

Newton's First Law

An object at rest stays at rest and an object in motion stays in motion unless acted on by an unbalanced force.

Newton's Second Law

Acceleration is proportional to the net force and inversely proportional to mass; F = m a.

F = m a meaning

Force equals mass times acceleration; more force or less mass increases acceleration.

In vacuum, why do objects fall at the same rate?

Gravity accelerates all masses equally (neglecting air resistance); objects fall at the same rate g ≈ 9.8 m/s^2.

Mass vs Weight

Mass is the amount of matter; weight is the gravitational force on that mass, W = m g.

How does distance affect gravitational force?

Gravitational force increases as objects get closer and decreases with distance; inversely proportional to distance squared.

Centripetal force

The inward force that keeps an object moving in a circle toward the center.

Magnetic forces are created by

Moving electric charges; magnets interact with certain metals.

Magnetic force and distance

Magnetic force decreases as the distance between objects increases.

Friction

Opposes motion between touching surfaces; static friction prevents motion from starting; sliding (kinetic) friction occurs when moving.

Balanced vs Unbalanced forces

Balanced: net force is zero, object remains at rest or moves with constant velocity. Unbalanced: net force is nonzero, causes acceleration.

Electric vs Magnetic forces relation

Both arise from electric charges; electric forces from stationary charges, magnetic from moving charges; related through electromagnetism.

Charges: like vs opposite

Like charges repel; opposite charges attract.