Correct Option
The correct option is (b).
Explanation
The rate of motion determines how fast or slow an object moves. This rate is quantified by the concept of speed, which relates the distance covered by an object to the time taken to cover that distance.
Statement-wise Analysis
- Statement 1 is Incorrect. Different objects move at different rates. Some objects move faster than others, meaning they cover a given distance in less time, while others move slower and take more time to cover the same distance. Therefore, not all objects take the same amount of time to cover a given distance.
- Statement 2 is Correct. The most common method to measure the rate of motion is to calculate the distance travelled by an object in a unit of time. This quantity is referred to as speed. The SI unit of speed is meters per second (m/s).
- Statement 3 is Incorrect. The speed of an object is not required to be constant. In most practical scenarios, objects undergo non-uniform motion, where their speed varies over time. For example, a car moving through traffic changes its speed frequently. If an object moves at a constant speed, it is said to be in uniform motion, but this is a specific case, not a universal rule.
Key Takeaway
Speed is the scalar quantity representing the rate of motion, defined as distance travelled per unit time. Motion can be uniform (constant speed) or non-uniform (variable speed).