Question: Unit Exam - Energy and Work
The object has a mass of 4.0 kg. What is the potential energy of the object at point A?
g = 10.00 m/sĀ²
Height (m) vs. Time (s)
Height (m)
Time (s)
A
30 J
600 J
300 J
1. **State the problem:** We need to find the potential energy of an object of mass $4.0$ kg at point A, where the height is approximately $7.5$ m.
2. **Formula for potential energy:** Potential energy (PE) is given by the formula:
$$PE = mgh$$
where:
- $m$ is the mass of the object,
- $g$ is the acceleration due to gravity,
- $h$ is the height above the reference point.
3. **Given values:**
- $m = 4.0$ kg
- $g = 10.00$ m/s$^2$
- $h = 7.5$ m (height at point A from the graph)
4. **Calculate potential energy:**
$$PE = 4.0 \times 10.00 \times 7.5$$
$$PE = 300$$
5. **Interpretation:** The potential energy of the object at point A is $300$ joules.
**Final answer:**
The potential energy at point A is **300 J**.