1. **State the problem:** An object of mass 5 kg is dropped from a height of 100 m. We need to find the height at which its kinetic energy (KE) is twice its potential energy (PE).
2. **Formulas and rules:**
- Potential energy at height $h$ is given by $PE = mg h$ where $m$ is mass, $g$ is acceleration due to gravity, and $h$ is height.
- Kinetic energy is $KE = \frac{1}{2} m v^2$.
- Total mechanical energy at the start (height 100 m) is $E = mg \times 100$.
- Since energy is conserved, $E = PE + KE$ at any height.
3. **Set up the equation:**
We want $KE = 2 PE$.
Using conservation of energy:
$$mg \times 100 = PE + KE$$
Substitute $KE = 2 PE$:
$$mg \times 100 = PE + 2 PE = 3 PE$$
So,
$$PE = \frac{mg \times 100}{3}$$
4. **Calculate height $h$:**
Since $PE = mg h$,
$$mg h = \frac{mg \times 100}{3}$$
Cancel $mg$ on both sides:
$$h = \frac{100}{3} \approx 33.33$$
5. **Answer:** The height at which the kinetic energy is twice the potential energy is approximately 33.33 meters.
Kinetic Potential 13E0Df
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