An automobile starting from rest with constant acceleration a passes 1st bridge at t_1 = 5 s and 2nd bridge at t_2 = 10 s. Distance between bridges is 75 m. What is acceleration a?
1. x_1 = 0.5 * a * 25 = 12.5a. 2. x_2 = 0.5 * a * 100 = 50a. 3. 50a – 12.5a = 37.5a = 75 -> a = 2 m s^-2.