Stress and strain

Need to know

What you need to know

• Stress is symbolised by $\sigma$ (sigma).
• It measures the internal force acting on a material per unit cross-sectional area.
• The SI unit for stress is the Pascal (Pa), where 1 Pa = 1 N m⁻².
• High stress can be achieved with a large force or a very small area, explaining why sharp objects cut easily.

Explanation

Stress and strain

1. Stress is symbolised by $\sigma$ (sigma).
2. It measures the internal force acting on a material per unit cross-sectional area.
3. The SI unit for stress is the Pascal (Pa), where 1 Pa = 1 N m⁻².
4. High stress can be achieved with a large force or a very small area, explaining why sharp objects cut easily.