Average Velocity and Constant Acceleration practice problems for the FE Civil exam

When acceleration is constant, the average velocity over an interval is simply the mean of the initial and final velocities, and displacement is that average multiplied by the elapsed time. This shortcut solves a large share of the kinematics items on the FE Civil exam without touching the quadratic form of the equation, and it is faster and less error-prone when the two end velocities are known. The condition matters: the arithmetic mean of the end velocities is the average velocity only while acceleration is constant. If the problem describes a changing acceleration, or a stage where the body is coasting and then braking, split it into intervals and apply the relation to each one separately. Signs carry the geometry. Choose a positive direction before writing anything, then give every velocity and acceleration its sign relative to that choice; deceleration is acceleration with the opposite sign to the motion, not a separate quantity. Watch the difference between distance and displacement as well, because a body that reverses direction covers more distance than the net displacement the formula returns. Braking problems are the most common application: given an initial speed and a stopping distance, the average velocity is half the initial speed because the final velocity is zero.