A 420 km long road consists of two parts. The bend after the first straight section of the road, which is 240 km long, causes an angle of 105° with the remaining second section. While the first vehicle reaches the end of the road on a different short and straight path, the second vehicle starts from the same place at the same time and continues along the road. (a) If both vehicles travel at a constant speed of 60 km/h, how long before the first vehicle reaches the end of the road before the second vehicle? (b) If the first vehicle takes the same shortcut again at a constant speed of 60 km/h, what constant speed must the second vehicle have to reach the end of the road at the same time as the first vehicle? (Hint: use your vector knowledge)