5. An ideal spring is compressed 15 cm on a horizontal surface. When released, it accelerates a 1 kg block along a frictionless surface. It then encounters a rough surface with a coefficient of kinetic friction of 0.4. The 6 block comes to rest after travelling 50 cm. Determine the spring constant of the spring. 6. A 2000 kg car travelling east at 24 m/s enters an icy intersection and collides with a 3600 kg truck travelling at 10 m/s [S20 W]. If they become coupled together in the collision, what is their velocity (speed and direction) immediately after the impact