Forces and Work in Car Crashes

Physics News On Car Crashes

As fall break approaches, many teachers and students have been reminding me to drive safely on my journey back to Connecticut. Although said as polite gesture, it actually got me thinking about physics. Despite how safely you may actually drive, there is a large part of driving you cant control, which is where the safety of the car becomes important. We have already discussed how cars experience acceleration, deceleration (linearly and radialy), and frictional forces. However, a very important component of car safety involves how well the car handles the work done on it, also known as the magnitude of force over a certain distance. This explains why crash tests are so important for cars. Companies must run simulations of cars hitting solid objects and rolling over in order to see how well the car withstands the force and work acted on it. These considerations determine how big the crumple distance of compartments are, the materials used, and structure of the car. For example, certain parts of the car have mechanisms or small structures inside them to take the force over a certain distance. If a car didn’t have these precautions, the force would project a certain distance into the car. The structure of a car is built around displacing the force through multiple places and distances. As seen in the problems from our peer workshops, crumple zones are similar to why people wear helmets. Helmets and crumple zones manipulate the distance a force acts on a certain object. Besides adding small mechanisms, car companies also choose materials that can withstand the work done on them based on their strength and malleability. Basically, the thought put into the construction of a car revolves around the forces it may encounter and the work that may act on the car.

An example of a crash test: https://www.youtube.com/watch?v=_KCLyPip2Iw