Kinematics — if a body's velocity increases by equal amounts in equal intervals of time, the motion is described as:

Introduction / Context:
Describing motion accurately requires distinguishing among forms of acceleration. When the velocity change per unit time is constant, many equations of motion simplify and are widely used in mechanics of materials and dynamics.

Given Data / Assumptions:

• Velocity increases by equal amounts in equal time intervals.
• Motion is along a straight line for simplicity, but the definition holds vectorially.

Concept / Approach:

Acceleration is the rate of change of velocity with respect to time. If delta v / delta t is constant, acceleration is uniform (constant). This is the fundamental assumption behind the constant-acceleration kinematic equations.

Step-by-Step Solution:

Verification / Alternative check:

Plot v–t: a straight line slope indicates constant a; integrating gives x–t quadratic, consistent with s = ut + 0.5a*t^2.

Why Other Options Are Wrong:

Variable acceleration implies non-constant dv/dt. Retardation refers to negative acceleration (decreasing speed), which contradicts “increases”.

Common Pitfalls:

Confusing constant speed with constant acceleration; assuming acceleration constant only if force is constant without considering mass variations.

Final Answer:

a uniform acceleration