A sprinter can accelerate with constant acceleration for 4.0s before reaching top speed. He can run the 100-meter dash in 10s. What is his speed as he crosses the finish line? I need help with this problem. I know that for the last 6 seconds because he has reached top speed that he has constant velocity. During the first 4 seconds I must use a Uniformed Accelerated Motion formula, and I think I need to actually combine 2 of them together; however, I get an unrealistic answer, like 15m/s, which I know is incorrect. Please help me find the sprinter's speed as he crosses the finish line?