A body in one dimensional motion has zero speed at an instant. At that instant, it must have

Options

A. Zero velocity
B. Zero acceleration
C. Non-zero velocity
D. Non-zero acceleration

Answer

To solve the question, "A body in one-dimensional motion has zero speed at an instant. At that instant, it must have," we need to analyze the implications of having zero speed.

### Step-by-Step Solution:

1. **Understanding Zero Speed**:
- Speed is defined as the magnitude of velocity. If a body has zero speed at an instant, it means that its velocity is also zero at that instant.

2. **Implications of Zero Velocity**:
- When the velocity is zero, it indicates that the body is momentarily at rest. However, this does not provide information about the acceleration of the body at that instant.

3. **Acceleration Consideration**:
- Acceleration is defined as the rate of change of velocity. A body can have zero velocity while still experiencing acceleration. For example, when a ball is thrown upwards, it comes to a momentary stop at the highest point (zero velocity), but it is still under the influence of gravity, which provides a downward acceleration.

4. **Conclusion**:
- Therefore, at the instant when the speed of the body is zero, it must have zero velocity. However, the acceleration can be non-zero. Thus, the correct conclusion is that the body can have zero speed and zero velocity at that instant, but it may also have a non-zero acceleration.

### Final Answer:
At that instant, the body must have zero velocity.