Asked by Beth

A sprinter can accelerate with constant acceleration for 2.70 s before reaching top speed. He can run the 100-meter dash in 10 s. What is his speed as he crosses the finish line?

Please show me all the steps to solving this problem.

Thanks
Answered by bobpursley
Ok, during the acceleration phase, his average velocity was Vf/2, during the rest of the race, the velocity is Vf.

distance= distance accelerating+ steady running distance
100 = Vf/2 * 2.70+ Vf*(10-2.70)
100= Vf(10-2.70/2)
solve for Vf