Physics Formulas IGCSE

Physics Formulas for IGCSE: Key Concepts and Examples

The International General Certificate of Secondary Education (IGCSE) Physics curriculum covers a broad range of topics, requiring students to understand and apply various formulas. This article outlines some essential physics formulas for IGCSE, complete with explanations and examples to aid your understanding.

1. Kinematics

Speed, Distance, and Time

Formula: $ \text{Speed} = \frac{\text{Distance}}{\text{Time}} $

Example: If a car travels 150 km in 3 hours, the speed is:

$$ \text{Speed} = \frac{150 \text{ km}}{3 \text{ hours}} = 50 \text{ km/h} $$

Acceleration

Formula: $ a = \frac{\Delta v}{\Delta t} $

Example: If a car increases its velocity from 20 m/s to 30 m/s in 5 seconds, the acceleration is:

$$ a = \frac{30 \text{ m/s} - 20 \text{ m/s}}{5 \text{ s}} = 2 \text{ m/s}^2 $$

Equations of Motion

Formula 1: $ v = u + at $

Formula 2: $ s = ut + \frac{1}{2}at^2 $

Formula 3: $ v^2 = u^2 + 2as $

Example: For a car accelerating from rest ($ u = 0 $) at $ 3 \, \text{m/s}^2 $ for 4 seconds, the final velocity ($ v $) is:

$$ v = 0 + (3 \, \text{m/s}^2 \times 4 \, \text{s}) = 12 \text{ m/s} $$

2. Forces and Motion

Newton’s Second Law

Formula: $ F = ma $

Example: For a mass of 10 kg accelerating at $ 2 \, \text{m/s}^2 $, the force is:

$$ F = 10 \text{ kg} \times 2 \text{ m/s}^2 = 20 \text{ N} $$

Weight

Formula: $ W = mg $

Example: For a mass of 5 kg and $ g = 9.8 \, \text{m/s}^2 $, the weight is:

$$ W = 5 \text{ kg} \times 9.8 \text{ m/s}^2 = 49 \text{ N} $$

3. Energy

Kinetic Energy

Formula: $ KE = \frac{1}{2}mv^2 $

Example: For a mass of 2 kg moving at 3 m/s, the kinetic energy is:

$$ KE = \frac{1}{2} \times 2 \text{ kg} \times (3 \text{ m/s})^2 = 9 \text{ J} $$

Gravitational Potential Energy

Formula: $ GPE = mgh $

Example: For a mass of 3 kg at a height of 10 m, the gravitational potential energy is:

$$ GPE = 3 \text{ kg} \times 9.8 \text{ m/s}^2 \times 10 \text{ m} = 294 \text{ J} $$

4. Waves

Wave Speed

Formula: $ v = f\lambda $

Example: For a wave with a frequency of 50 Hz and a wavelength of 2 m, the speed is:

$$ v = 50 \text{ Hz} \times 2 \text{ m} = 100 \text{ m/s} $$

Frequency

Formula: $ f = \frac{1}{T} $

Example: If the period ($ T $) of a wave is 0.01 seconds, the frequency is:

$$ f = \frac{1}{0.01 \text{ s}} = 100 \text{ Hz} $$

5. Electricity

Ohm’s Law

Formula: $ V = IR $

Example: For a current ($ I $) of 2 A flowing through a resistor ($ R $) of 3 Ω, the voltage ($ V $) is:

$$ V = 2 \text{ A} \times 3 \Omega = 6 \text{ V} $$

Electrical Power

Formula: $ P = IV $

Example: For a current of 3 A and a voltage of 12 V, the power is:

$$ P = 3 \text{ A} \times 12 \text{ V} = 36 \text{ W} $$

6. Thermal Physics

Specific Heat Capacity

Formula: $ Q = mc\Delta T $

Example: For 2 kg of a substance with a specific heat capacity of 4200 J/kg°C and a temperature change of 5°C, the heat energy is:

$$ Q = 2 \text{ kg} \times 4200 \text{ J/kg°C} \times 5°C = 42000 \text{ J} $$

Latent Heat

Formula: $ Q = mL $

Example: For 1.5 kg of a substance with a latent heat of fusion of 334,000 J/kg, the heat energy is:

$$ Q = 1.5 \text{ kg} \times 334,000 \text{ J/kg} = 501,000 \text{ J} $$

Conclusion

Understanding and applying these fundamental physics formulas are crucial for excelling in the IGCSE Physics exam. By practicing these formulas and their applications through various problems and examples, students can build a strong foundation in physics concepts, preparing them for further studies and practical applications in the field of physics.

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