When an object covers equal distances in equal intervals of time in a straight line, the object is said to be in which type of motion?

Introduction / Context:
Motion can be classified in many ways, and one of the simplest and most important distinctions is between uniform and non-uniform motion. This question uses a standard textbook definition involving equal distances in equal intervals of time to test whether you can correctly name the type of motion described.

Given Data / Assumptions:

• The object moves along a path, which we can consider as a straight line for simplicity.
• In any equal time intervals (for example, every second or every minute), the object covers exactly the same distance.
• There is no mention of changing speed or acceleration.
• We must select the appropriate type of motion from the options given.

Concept / Approach:
Uniform motion is defined as motion in which an object covers equal distances in equal intervals of time, no matter how small those intervals are, provided they are equal. In such motion, the speed of the object remains constant. Non-uniform motion, by contrast, involves varying speeds and unequal distances in equal times. The options “linear” and “translational” describe direction and type of motion but not whether the speed is constant, and “equilibrium” refers to forces rather than motion. Therefore, the correct term here is uniform motion.

Step-by-Step Solution:
Step 1: Focus on the key phrase in the question: “equal distances in equal intervals of time.” Step 2: Recall the standard definition from physics: motion is called uniform when equal distances are covered in equal times. Step 3: Recognise that in uniform motion, the speed of the object remains constant. Step 4: Compare with “linear motion,” which only indicates that the path is a straight line, and with “translational motion,” which refers to motion where all parts of a body move in the same direction. Step 5: See that the question is clearly about speed constancy, not about the shape of the path, so “uniform” is the correct answer.

Verification / Alternative check:
Consider a car traveling along a straight road at a constant speed of 40 km/h. Every hour it moves 40 km, so the distance covered in equal time intervals is equal, fitting the definition of uniform motion. If the car speeds up or slows down, the distances covered in each hour become different, and the motion is no longer uniform. Textbooks explicitly state “equal distances in equal intervals of time” as the hallmark of uniform motion, which directly matches the wording of this question.

Why Other Options Are Wrong:
Linear: Linear motion simply means motion along a straight line; it can be either uniform or non-uniform, depending on whether speed is constant.

Translational: Translational motion refers to overall movement of a body from one location to another, where all parts of the body move parallel to each other; it does not specify constant speed.
Equilibrium: This term refers to the balance of forces (net force equal to zero) and does not by itself describe the pattern of distances covered in time.

Common Pitfalls:
Some learners may fixate on the idea of motion in a straight line and choose “linear” without noticing that the key feature in the statement is about equal distances and time intervals. Others may recall the term “translational motion” from rigid body dynamics and confuse it with uniformity. Always pay attention to the definition given in the question; whenever equal distances in equal time intervals appear, think of uniform motion.

Final Answer:
An object that covers equal distances in equal intervals of time is in Uniform motion.