- Determine the magnitude of the momentum just after the collision. - Is this the same as the magnitude of the momentum just before the collision? Explain why or why not. From Lesson 2 Using the principle of conservation of momentum the police determined that Bill's truck was travelling at 2.3 m/s before the collision, and Kathy's car was travelling at 15 m/s before the collision. .What is the kinetic energy of the vehicles before and after the collision? -Is kinetic energy conserved? If kinetic energy is not conserved, what does this tell us about the type of collision? From Lesson 3 You have already determined the magnitude of the momentum of the combined vehicles just after impact and the kinetic energy before and after the impact. The following vector diagram illustrates the direction of the momentum vector based on evidence from the scene. The two momentum vectors before the collisions are represented in blue. The momentum after the collision is in red. Adding the two momentum vectors before the collision equals the momentum after the collision, according to the law of conservation of momentum. momentum of combined vehicles momentum of car ' "\\lOU" momentum oftruck While the opening photo suggests a much more complex collision than the given diagram, assume that the diagram shows exactly what happened. - Using this vector diagram and your calculated value for the momentum of the combined vehicles, verify the police calculations and determine the momentum and velocity of Bill's truck just before the collision. - Using this vector diagram and your calculated value for the momentum of the combined vehicles, verify the police calculations and determine the momentum and velocity of Kathy's car just before the collision. - Does your analysis prove, beyond a reasonable doubt, that Kathy was, in fact, travelling at the speed limit of 50 km/h just prior to the accident? What assumptions did you make in your solution to determine this? j WmOn October 1 ,Kathy Johnson (not her real ' - 'name) was driving home from work in her red _ ' car. As she approached the University Drive " \"intersection, Bill Peterman (not his real name), driving his white pickup truck, attempted to cross the same intersection on his way to class. Unfortunately, they collided in the centre of the intersection. As seen in this photo, both vehicles became joined and moved off to the side of the intersection before coming to rest. When the police arrived and began taking statements, Bill claimed that Kathy was well back from the intersection when he attempted to cross and that her high rate of speed was to blame for the accident. At the same time, Kathy insisted she was travelling at the posted speed limit, 50 km/h, and that Bill entered the intersection without proper care and attention. Both Kathy and Bill received medical attention for non-life- threatening injuries. The property damage to both vehicles was substantial. The case is now before the courts to decide who will pay for the damages. In addition, the police have charged Kathy with driving in excess of the posted speed limit. In her defence, Kathy has hired a consultant to perform a crash analysis hoping that it will conrm her Speed prior to the collision. The intent of this analysis is to prove, beyond a reasonable doubt, that she was actually travelling at the speed limit just prior to the accident. How is this possible? How can conservation principles related to momentum and energy be applied to analyze and understand collisions? From Lesson 1 The mass of the truck is 3200 kg, and the mass of the car is 2800 kg. Based on the length of the skid marks at the scene and the mass of the vehicles, police estimate that the combined mass was moving at 7.0 m/s just after impact. From this point, the two vehicles slid and came to rest at the comer of the inter