A car is traveling at 60 mi/h down a highway. a)What magnitude of acceleration does it need to have to come to a complete stop in a distance of 200 ft? b)What acceleration does it need to stop in 200 ft if it is traveling at 110 mi/h ?

Answer 1

60 mph = 88 ft/s

a) the average speed while stopping is 30 mph or 44 ft/s
... the stopping time is
... 200 ft / 44 ft/s

divide the initial speed by the stopping time to find the acceleration

b) same process as a) but with a different initial speed