IBDP Physics Core Concepts - Mechanics & Fields

Front

Instantaneous vs. Average Velocity

Back

**Average velocity** is total displacement divided by total time (v = Δs/Δt). **Instantaneous velocity** is the limit of average velocity as Δt approaches zero, represented by the slope of the tangent on a displacement-time graph.

Front

Projectile Motion Independence

Back

In projectile motion (ignoring air resistance), the horizontal and vertical components of motion are **independent**. The horizontal velocity is constant (ax=0), while the vertical motion is subject to constant downward acceleration (g).

Front

Newton's Third Law Pairs

Back

For every action force, there is an equal and opposite reaction force. These forces must act on **different** bodies, be of the **same type** (e.g., both gravitational), and act along the same line. They do not cancel out for a single object.

Front

Impulse and Momentum

Back

Impulse (J) is the change in momentum (Δp) and equals the product of force and time (J = FΔt = Δp). For a constant mass, this becomes FΔt = mΔv. A larger impact time reduces the average force experienced.

Front

Principle of Conservation of Momentum

Back

Total linear momentum of an isolated system (no external net force) remains constant. In elastic collisions, kinetic energy is also conserved; in inelastic collisions, kinetic energy is transformed into other forms (e.g., heat), but momentum is conserved.