Sidney's group came up with a design for the seat belt but had to figure out whattype of material to use. They picked two fabrics: one that was very rigid with littlegive and a second fabric that was stretchy. They made the two belts, got somemotorized cars and put action figures into the cars, one car per seat belt design.Then they ran the cars into a wall of the classroom. Predict which belt they choseand why.The stretch seat belt: for every action there is a reaction. The stretch belt letsyou move forward and then you move back again.The non-stretch seat belt: with no seatbelt to stop the driver with the car, thedriver flies free until stopped suddenly by impact on the steering column so thenon-stretch belt keeps the driver from flying free.The non-stretch seat belt holds the driver immobile against the seat as the carcrashed.The stretch seat belt: some stretch in the seatbelts will reduce the averageimpact force by extending the stopping distance of the passenger
