Problem 7: A car starts at rest and moves along a perfectly straight highway with an acceleration of a, = 10 m/s? for a certain amount of time t1. It

then moves with constant speed (zero acceleration) for a time t2 and finally decelerates with an acceleration a2 = -10 m/s² for a time t3 until it comes to a complete stop. The total time of motion is t + t2 + t3 = 25 s. The total distance travelled by the car is 1 km. Find t2.