Question

A car traveling at 60 km/h is brought to rest over a distance of 100 m. What is the
acceleration? Give the answer in m/sZ

Answer 1

Convert speed: 60 km/h = 60·1000/3600 = 16.6667 m/s.
Use v^2 = v0^2 + 2as with v = 0:
a = -v0^2/(2s) = -(16.6667^2)/(2·100) = -277.78/200 = -1.3889 m/s^2.

So a ≈ -1.39 m/s^2 (magnitude 1.39 m/s^2, negative sign = deceleration).