Newton's Second Law of Motion – Vocabulary

Vocabulary flashcards covering key terms and concepts from the Day 2 Newton's Second Law notes.

Newton's Second Law of Motion

The acceleration of an object is directly proportional to the net force acting on it, in the same direction as the net force, and inversely proportional to the object's mass (a = Fnet / m; Fnet = m a).

Net force

The vector sum of all forces acting on an object.

Acceleration

The rate of change of velocity; in this context, a = F_net / m.

Mass

A measure of an object's inertia; greater mass means smaller acceleration for the same net force.

Force

A push or pull on an object that can cause motion; measured in newtons.

F = m a (Equation for acceleration)

The relationship showing that net force equals mass times acceleration; rearranged as a = F_net / m.

Free fall

Motion under gravity with negligible air resistance; objects accelerate at g.

Gravity (g)

Acceleration due to Earth's gravity, about 9.8–10 m/s^2.

Terminal velocity

The constant velocity reached when drag force equals the weight, so net force is zero.

Air resistance

Opposing force from air that increases with speed and reduces acceleration.

Weight

The force of gravity on an object; W = m g.

Vacuum (feather and coin demonstration)

In a vacuum, a feather and a coin fall at the same rate because there is no air resistance.

Non-free fall

Motion in which forces other than gravity (like air resistance) affect acceleration, making it less than g.

Parachute mass effect

With the same parachute, heavier bodies reach a higher terminal velocity and fall faster in air than lighter ones.

a ∝ 1/m (acceleration and mass)

For a fixed net force, halving the mass doubles the acceleration.

a ∝ F_net (acceleration and net force)

For a fixed mass, increasing net force increases acceleration.

Free-fall independence of mass

In the absence of air resistance, all objects accelerate at the same rate g regardless of mass.

Weight-to-mass ratio in free fall

W/m = g; constant for all objects at a given location, leading to the same acceleration when air resistance is negligible.

Feather-coin vacuum vs air

In air, drag affects speeds differently; in a vacuum, both fall with acceleration g.