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?

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Answer 1 · 2017-05-06T08:52:50

#208.bar 3ms^-2#

Using the kinematic equation

#v=u+at#
where symbols have their respective meanings. Inserting given values in SI units, and assuming that deceleration is constant, we have

#0=(60xx10^3)/3600+axx0.08#
#0=>a=-(60xx10^3)/3600xx1/0.08=-208.bar 3ms^-2#
#-ve# sign shows it is deceleration.

This is deceleration of car, its occupants including driver.