Define kinetic energy and potential energy - Leaving Cert Physics - Question a - 2016

To calculate the potential energy (PE) of the egg before it is dropped, we use the formula: $PE = mgh$ where:

• $m = 0.052$ kg (mass of the egg converted from 52 g)
• $g = 9.8$ m/s² (acceleration due to gravity)
• $h = 2$ m (height from which the egg is dropped)

Substituting the values in: $PE = 0.052 imes 9.8 imes 2 = 1.0196\ ext{ J}$ Rounding off, the potential energy is approximately $1.02 ext{ J}$.

To calculate the velocity ($v$) of the egg as it hits the ground, we can use the conservation of energy principle, which states that the potential energy (PE) at the top converts to kinetic energy (KE) at the bottom: $PE = KE$ This means: $mgh = \frac{1}{2} mv^2$ Cancelling the mass ($m$) from both sides: $gh = \frac{1}{2} v^2$ Rearranging for $v$ gives us: $v^2 = 2gh$ Substituting the given values: $v^2 = 2 \times 9.8 \times 2 \implies v = \sqrt{2 \times 9.8 \times 2} = \sqrt{39.2} \approx 6.26 \text{ m/s}$

The egg can be protected from breaking by implementing cushioning materials during the drop. For instance, placing the egg inside a padded container or wrapping it in soft materials (like foam or bubble wrap) can help absorb the impact at the moment of collision, reducing the force exerted on the egg.

One everyday application of this principle is the use of airbags in vehicles. Airbags inflate upon impact to cushion occupants, reducing the force of a sudden stop, similar to how protective materials can help prevent an egg from breaking when it lands.