Final answer:
The speed and direction of the two cars immediately after impact, assuming they lock together, is 3.33 m/s west. This is calculated using the law of conservation of momentum.
Step-by-step explanation:
To determine the speed and direction of the two cars immediately after the impact, we can use the law of conservation of momentum. Momentum before the collision must equal the momentum after the collision if they lock together. The SUV's momentum can be calculated as the product of its mass and velocity (2600 kg * 15 m/s = 39000 kg*m/s west), and the sedan's momentum is (1300 kg * 20 m/s = 26000 kg*m/s east). Since they are traveling in opposite directions, we consider one of them as negative for the calculation.
Thus, the total momentum before the collision is 13000 kg*m/s west (39000 kg*m/s - 26000 kg*m/s). After the collision, the total mass of the locked cars is 2600 kg + 1300 kg = 3900 kg. To find the speed, we divide the total momentum by the total mass:
Speed = Total Momentum / Total Mass = 13000 kg*m/s / 3900 kg = 3.33 m/s
Therefore, the speed of the two cars locked together immediately after the collision is 3.33 m/s, in the westward direction (the direction of the positive momentum).