A car with a total mass of 1400kg (including occupants), traveling at 60kmh^-1 hits a large tree and stops in 0.08seconds. What is the magnitude of the deceleration of the 70kg driver of the car if he is wearing a properly fitted seat belt?
Using the kinematic equation
where symbols have their respective meanings. Inserting given values in SI units, and assuming that deceleration is constant, we have
This is deceleration of car, its occupants including driver.