3. How fast will a runner be going if he accelerates from rest at 3.0 m/s2 for a distance of 2.5 m? 4. An ice skater accelerates backward for 5.0 seconds to a final speed of 12 m/s, moving backward. If the acceleration backward was at a rate of 1.5 m/s2, what was the skater's initial speed? 5. A freight train moving at an initial speed of 40 m/sec puts on its brakes, producing a deceleration of 0.50 m/sec2 (a) How fast will it be going after it has traveled 100 m? (b) How long will it take the train to travel the next 100 m? 6. A child throws a ball straight down off the balcony of an apartment building at a speed of 7.5 m/s. (a) Calculate the position and velocity of the ball 2.0 seconds later