Which of the following statements is not correct?a)The zero velocity o...
The sign of acceleration does not tell us whether the particle's speed is increasing or decreasing. The sign of acceleration depends on the choice of the positive direction of the axis.
For example: If the vertically upward direction is chosen to be positive direction of the axis, the acceleration due to gravity is negative. If a particle is falling under gravity, this acceleration though negative results in increase in speed.
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Which of the following statements is not correct?a)The zero velocity o...
Explanation:
The correct answer is option 'C' - The sign of acceleration tells us whether the particle's speed is increasing or decreasing.
Reason:
The sign of acceleration does not directly tell us whether the particle's speed is increasing or decreasing. The sign of acceleration only indicates the direction of the acceleration vector, not its magnitude.
Example:
Consider a particle moving in a straight line. If the particle is moving in the positive direction and has a positive acceleration, it means that the particle is speeding up. However, if the particle is moving in the positive direction and has a negative acceleration, it means that the particle is slowing down. Similarly, if the particle is moving in the negative direction and has a positive acceleration, it means that the particle is slowing down, while a negative acceleration means that the particle is speeding up.
Key Points:
- The sign of acceleration indicates the direction of the acceleration vector, not whether the particle's speed is increasing or decreasing.
- The magnitude of acceleration determines the rate of change of velocity, which indirectly affects the particle's speed. If the magnitude of acceleration is positive, the particle's speed may increase, while a negative magnitude of acceleration may cause the particle's speed to decrease.
- To determine whether the particle's speed is increasing or decreasing, one needs to consider the sign and magnitude of both velocity and acceleration vectors.
Conclusion:
The statement that the sign of acceleration tells us whether the particle's speed is increasing or decreasing is not correct. The sign of acceleration only indicates the direction of the acceleration vector, while the magnitude of acceleration determines the rate of change of velocity, which indirectly affects the particle's speed.
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