Answer:
Assuming starting at zero velocity: at 4 seconds speed is 8 m/s (2m/s^2 * 4 seconds) and distance is 16 m (average speed is 4 m/s * 4 seconds). The remaining 84 meters (at 8 m/s) takes 10.5 seconds.
So total time to run 100 meters is 14.5 seconds.
Step-by-step explanation: