A gas filled ballon moves up because ____.

Options

A. gravity force does not act on the balloon
B. there is no frictional force on the balloon
C. upward force on the balloon is more than gravitational force
D. upward force on the balloon is more than frictional force

Explanation

**Step-by-Step Solution:**

1. **Understanding Forces Acting on the Balloon:**
- A gas-filled balloon experiences two main forces: the gravitational force acting downward and the buoyant force acting upward.

2. **Defining Gravitational Force:**
- The gravitational force is the force that pulls objects toward the center of the Earth. It acts on the balloon and tries to pull it down.

3. **Defining Buoyant Force:**
- The buoyant force is the upward force exerted by the fluid (in this case, air) surrounding the balloon. This force is due to the pressure difference in the fluid.

4. **Comparing Forces:**
- For the balloon to move upward, the buoyant force must be greater than the gravitational force acting on it. If the upward force (buoyant force) exceeds the downward force (gravitational force), the balloon will rise.

5. **Conclusion:**
- Therefore, a gas-filled balloon moves up because the upward force (buoyant force) on the balloon is greater than the gravitational force acting on it.

**Final Answer:**
A gas-filled balloon moves up because the upward force on the balloon is more than the gravitational force.

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