A car moving with a constant speed on a straight track takes a band in a curve with the same speed. Due to this

Options

A. The magnitude of its velocity is changed
B. Its acceleration is zero
C. Its velocity is not changed
D. Its velocity is changed

Answer

To solve the problem, we need to analyze the situation of a car moving with constant speed on a straight track and then taking a bend in a curve while maintaining that same speed.

### Step-by-Step Solution:

1. **Understanding Velocity and Speed**:
- Speed is a scalar quantity that refers to how fast an object is moving, regardless of its direction.
- Velocity is a vector quantity that includes both the speed of the object and the direction in which it is moving.

2. **Initial Condition**:
- The car is initially moving in a straight line at a constant speed. Here, both the magnitude and direction of the velocity are constant.

3. **Taking a Bend**:
- When the car takes a bend, it continues to move at the same speed, but its direction changes. This means that while the magnitude of the velocity (speed) remains constant, the direction of the velocity vector changes.

4. **Effect on Velocity**:
- Since velocity is a vector, a change in direction means that the velocity of the car has changed, even though the speed remains the same.

5. **Acceleration**:
- Acceleration is defined as the rate of change of velocity with respect to time. Since the direction of the velocity is changing as the car takes the bend, the car is experiencing centripetal acceleration directed towards the center of the curve.

6. **Conclusion**:
- Therefore, the correct conclusion is that the velocity of the car has changed due to the change in direction, even though the speed remains constant. Thus, the correct option is:
- **Option D: Its velocity is changed.**

### Summary of Options:
- **Option A**: The magnitude of its velocity changed. (Incorrect, as speed remains constant)
- **Option B**: Its acceleration is zero. (Incorrect, as there is centripetal acceleration)
- **Option C**: Its velocity is not changed. (Incorrect, as the direction of velocity changes)
- **Option D**: Its velocity is changed. (Correct, due to change in direction)