These problems are an introduction to perfectly plastic impact (which we will cover in Sec...

These problems are an introduction to perfectly plastic impact (which we will cover in Section 5.2). In each problem, model the vehicles A and C as particles and treat the swarm of bugs B hitting the vehicles as a single particle. Also assume that the swarm of bugs sticks perfectly to each vehicle (this is what is meant by a perfectly plastic impact).

Figure P5.21

An 80,000 lb semitruck A (the maximum weight allowed in many states) is traveling at 70 mph when it encounters a swarm of dragonflies B. The swarm is traveling at 33 mph in the opposite direction of the truck. Assuming that the entire swarm sticks to the truck, the mass of each dragonfly is 0.25 g, and that all of these dragonflies do not significantly damage the truck, how many dragonflies must have hit the truck if it slows down by 2 mph on impact? If the same number of dragonflies hit a small SUV C weighing 3000 lb, by how much will the SUV slow down?