Find:
a) t
b) a

Solution:
a) Vavg = (Vf + Vi)/2

Convert 30 mi/hr to ft/sec:
(30 mi/hr)(5280 ft/1mi)(1 hr/3600 sec)
= 44 ft/sec

Vavg = (44 ft/sec + 0)/2
Vavg = 22 ft/sec

d = Vavg(t)
100 ft = (44 ft/sec)t
t = 100 ft/44 ft/sec
t = 2.27 sec ANS

b) a = (Vf - Vi)/t
a = (44 ft/sec - 0)/2.27 sec
a = 19.4 ft/sec^2 ANS

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1st step: Find the time

Speed = distance /time
44 = 100feet/t
t = 2.27 seconds.

2nd step: Find acceleration
V = Vo + at

30 = 0 +a(2.27)
30/2.27 = a
a =13.2 ft/s^2 ultimate reality1