A car is traveling at an initial velocity of 15 m/s along a straight road; it begins to accelerate at a constant rate. Forty seconds later the velocity of the car is 28 m/s (in the same direction). The average velocity of the car during the 40-second interval is
A) 15 m/s.
B) 28 m/s.
C) 22 m/s.
D) 0 m/s.

Question

Quizplus · Accepted Answer

The average velocity can be calculated by taking the average of the initial and final velocities since the acceleration is constant. Thus, $ \frac{15 m/s + 28 m/s}{2} = 21.5 m/s $, which is not an option provided. However, the correct approach to find the average velocity over a time interval, given constant acceleration, is to use the formula for average velocity $ v_{avg} = \frac{v_i + v_f}{2} $, where $v_i$ is the initial velocity and $v_f$ is the final velocity. This calculation indeed results in $21.5 m/s$, indicating a mistake in the provided options or in the interpretation. Given the options, the closest correct answer based on the calculation would be 22 m/s, acknowledging a potential error in the question or answer choices.

A Car Is Traveling at an Initial Velocity of 15