Question

A race car completes the final lap of a race on a 2-kilometer circular track. At the start of the lap, it crosses the line at 60 meters/second. It completes the lap 28.57 seconds later, crossing the line at 85 meters/second. Calculate the displacement and average acceleration of the car within the span of 12 seconds.
A. Displacement is 0 meters, and acceleration is 0.88 meters/second^2.
B. Displacement is 2,000 meters, and acceleration is 1.14 meters/second^2.
C. Displacement is 0 meters, and acceleration is 70.0 meters/second^2.
D. Displacement is 2,000 meters, and acceleration is 80.0 meters/second^2.
E. Displacement is 0 meters, and acceleration is 0.70 meters/second^2.

Answer 1

The displacement of an object is the difference between the final position and the initial position. Since the race car rounded the circular track, the displacement is equal to 0 meters. The acceleration, if we assume it to be constant all throughout, should be equal to,
                             (85 m/s - 60 m/s) / (28.57 s) = 0.88 m/s²
Thus, the answer to the question above is letter A.