Please solve

. A Japanese bullet train slows from a speed of 50 m/sec to a speed of 40 m/sec in 500m. What is its acceleration? 40 m ? 50) on 2 + zu (500 ) S 1600 = 3, 600 + 1000 a a = _ 2m 7. A rock is dropped from a bridge and hits the water 3.2 seconds later. How high is the bridge? (Remember that you determined the acceleration due to gravity in class.) 8. A football player can accelerate at 2 m/s . If he starts from rest, how long will it take him to travel 16 m? You may use the grid to solve the problem graphically or you may use a mathematical representation