Correct Option
The correct option is (c) 2 and 3 only.
Explanation
Acceleration is a vector quantity defined as the rate of change of velocity with respect to time. It describes how quickly the velocity of an object is changing in terms of magnitude or direction.
Statement-wise Analysis
- Statement 1 is Incorrect. Acceleration is the measure of the change in velocity per unit time. The measure of distance covered per unit time is defined as speed.
- Statement 2 is Correct. An object is in uniform motion when it moves with a constant velocity (constant speed in a fixed direction). Since there is no change in velocity over time, the acceleration is zero.
- Statement 3 is Correct. Acceleration can act in the direction of motion (resulting in an increase in speed) or against the direction of motion (resulting in a decrease in speed). When acceleration acts opposite to the direction of velocity, it is often termed retardation or deceleration.
Key Takeaway
Acceleration is strictly the rate of change of velocity, not distance. In uniform motion, velocity is constant, meaning acceleration is zero. It is a vector quantity that can oppose motion (retardation).