Which of the following statement is not true regarding the Newton's third law of motion?

Options

A. To every action there is always an equal and opposite reaction.
B. Action and reaction act on the same body.
C. There is no cause-effect relation between action and reaction.
D. Action and reaction forces are simultaneous forces.

Explanation

To determine which statement is not true regarding Newton's third law of motion, let's analyze each option step by step.

### Step-by-Step Solution:

1. **Understanding Newton's Third Law of Motion**:
- Newton's third law states that for every action, there is an equal and opposite reaction. This means that forces always come in pairs.

2. **Analyzing the Statements**:
- **Statement A**: "To every action, there is always equal and opposite reaction."
- This statement is true. It accurately reflects Newton's third law.

- **Statement B**: "Action and reaction act on the same body."
- This statement is false. According to Newton's third law, action and reaction forces act on different bodies. For instance, if body A exerts a force on body B, then body B exerts an equal and opposite force on body A. They do not act on the same body.

- **Statement C**: "There is no cause-effect relation between action and reaction."
- This statement is true. In the context of Newton's third law, we cannot identify one force as the cause and the other as the effect; they are simply two forces that occur simultaneously.

- **Statement D**: "Action and reaction forces are simultaneous forces."
- This statement is also true. Action and reaction forces occur at the same time.

3. **Identifying the Incorrect Statement**:
- After analyzing all the statements, the only incorrect statement is **Statement B**: "Action and reaction act on the same body."

### Conclusion:
The statement that is not true regarding Newton's third law of motion is **Statement B**: "Action and reaction act on the same body."

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