A body with a mass of 12 kg is hanging in a static condition 20 meters above the ground. It is now allowed to fall to the ground. 3.1 How much kinetic energy did it possess in the split second before it struck the ground? 3.2 Briefly explain how you did this calculation, referring to the energy characteristics.

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To solve the problem, we will use the principles of gravitational potential energy and kinetic energy.

### Known Conditions:
- Mass of the body, $$ m = 12 \, \text{kg} $$
- Height from which it falls, $$ h = 20 \, \text{m} $$
- Gravitational acceleration, $$ g = 9.81 \, \text{m/s}^2 $$ (standard value)

### 3.1 Kinetic Energy Just Before Impact

The kinetic energy (KE) of the body just before it strikes the ground can be calculated using the principle of conservation of energy. The potential energy (PE) at the height will convert entirely into kinetic energy just before impact.

1. **Calculate the potential energy at the height:**
   $$
   PE = m \cdot g \cdot h
   $$

2. **Since all potential energy converts to kinetic energy just before impact:**
   $$
   KE = PE
   $$

Now, let's calculate the potential energy and thus the kinetic energy.

### Calculation

Using the formula for potential energy:
$$
PE = m \cdot g \cdot h
$$

Substituting the known values:
$$
PE = 12 \, \text{kg} \cdot 9.81 \, \text{m/s}^2 \cdot 20 \, \text{m}
$$

Now, I will perform the calculation.
Calculate the value by following steps:
- step0: Calculate:
  $$12\times 9.81\times 20$$
- step1: Multiply the terms:
  $$117.72\times 20$$
- step2: Multiply the numbers:
  $$2354.4$$
The potential energy (and thus the kinetic energy just before impact) is calculated as follows:

$$
PE = 12 \, \text{kg} \cdot 9.81 \, \text{m/s}^2 \cdot 20 \, \text{m} = 2354.4 \, \text{J}
$$

### 3.2 Explanation of the Calculation

1. **Energy Characteristics**: 
   - When the body is at a height of 20 meters, it possesses gravitational potential energy due to its position in the gravitational field. This energy is given by the formula $$ PE = mgh $$.
   - As the body falls, this potential energy is converted into kinetic energy. The principle of conservation of energy states that energy cannot be created or destroyed, only transformed from one form to another.

2. **Conversion to Kinetic Energy**:
   - Just before the body strikes the ground, all the potential energy it had at the height of 20 meters has been converted into kinetic energy. Therefore, the kinetic energy just before impact is equal to the potential energy at the height.

Thus, the kinetic energy of the body just before it strikes the ground is $$ 2354.4 \, \text{J} $$.
Before hitting the ground, the body had 2354.4 joules of kinetic energy. simplify answer for explanation: The body's potential energy at 20 meters converts entirely to kinetic energy just before it strikes the ground, resulting in 2354.4 joules of kinetic energy.

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