A 75.0-kg person is riding in a car moving at 20.0 m/s when the car runs into a bridge abutment (see the following figure). a. Calculate the average force on the person if he is stopped by a padded dashboard that compresses an average of 1.00 cm. b. Calculate the average force on the person if he is stopped by an air bag that compresses an average of 15.0 cm.