Modeling relationships: car skid marks

This problem solving resource uses linear functions to model real world data about car skid marks. The work assumes students are familiar with substitution and drawing straight line graphs.

The problem is set in the context of investigating car accidents. When a car suddenly brakes to a stop, it can leave skid marks. These marks can be used to work out the speed of the car, possibly giving evidence that the driver was going over the speed limit. Two people are shown who try to work out a ‘rule of thumb’. Students are asked to evaluate the two approximations and explain which rule is the best one to use for any traffic accident.

Examples of student work are provided to allow for peer assessment. These are useful for highlighting different approaches to determining the ‘best’ rule.

This is a problem solving lesson from the Mathematics Assessment Resource Service, a collaboration between UC Berkeley and the Shell Centre team at the University of Nottingham. Further information on the collection is given here.