A car travelling at 81 km/h slams on the brakes. The car comes to a stop after 2.9 s. What is the force from the seatbelt acting on the driver if the driver has a mass of 72 kg? (Assume the driver's acceleration matches the car's)

a = 81 km/hr * (1000 m/km) * (1 hr/3600 s) / 2.9 s = ? m/s^2

f = m a = 72 kg * a = ? N