A 1900 kg car moving at 20.0 m/s crashes into a brick wall and is stopped. The driver's mass is 70.0 kg, and although the driver is not wearing his seatbelt, the air bag thankfully slows him to a stop in 0.100 s. What is the magnitude of the average force that the air bag exerts on the driver? ______________ (Side Note: Air bags and seat belts act to slow you to a rest in a longer time. By increasing the time, the force on your body decreases. An average force exceeding roughly 2.00 x 105 N will probably kill you.) How would you do this problem?