(20mi/hr)*(1609m/1mi)*(1hr/3600sec)=8.94m/s
a=(8.94m/s)/4sec=2.2m/s/s
If your acceleration was -3m/s/s and you stopped from an initial speed of 100m/s/s, how long did it take to stop?
a=Vf-Vo/t=(50mi/hr-30mi/hr)/4sec=(20mi/hr)/4sec=5mi/hr/sec
NOTE: You should stay in meters/second,
so switch the 20miles/hr to m/s!
(20mi/hr)*(1609m/1mi)*(1hr/3600sec)=8.94m/s
a=(8.94m/s)/4sec=2.2m/s/s
If your acceleration was -3m/s/s
and you stopped from an initial speed of 100m/s/s, how long did it take
to stop?
If a=Vf-Vo/t, then t=Vf-Vo/a, so
t=(0m/s-100m/s)/(-3m/s/s)=33.3 seconds