A-Level Physics - Core Concepts & Applications

Front

Define and distinguish between **Systematic** and **Random** errors.

Back

**Systematic Error:** A consistent, repeatable error associated with faulty equipment or calibration (e.g., a zero error). It affects **accuracy**. **Random Error:** Unpredictable variations in measurements due to observer limitations or environmental fluctuations. They affect **precision**.

Front

State the conditions for **Translational Equilibrium**.

Back

An object is in translational equilibrium if the **vector sum of all forces acting on it is zero** (ΣF = 0). This results in zero acceleration (constant velocity, which could be zero or non-zero).

Front

Explain the concept of a **Couple** and calculate its **Torque**.

Back

A **Couple** consists of two parallel, equal magnitude, but opposite direction forces that do not act along the same line. **Torque (Moment of a Couple):** τ = F × d Where 'F' is the magnitude of one force and 'd' is the perpendicular distance between the lines of action of the forces. It produces pure rotation without translation.

Front

Define **Principle of Conservation of Momentum**.

Back

The total linear momentum of a closed system of interacting bodies remains constant provided no **external resultant force** acts on the system. Formula: m₁u₁ + m₂u₂ = m₁v₁ + m₂v₂

Front

Define **Stress** and **Strain**.

Back

**Stress:** The force applied per unit cross-sectional area. Units: Pa (N/m²). σ = F / A **Strain:** The ratio of extension (ΔL) to the original length (L₀). It is a dimensionless ratio. ε = ΔL / L₀