Part A
Write your givens
Vi = 0 , Vf = 41 mi/h = 18.3 m/s
a = 2.35 m/s^2
Using the following formula:
a=(vf-vi)/t
Solve for t
t=(vf-vi)/a
Substitute
t=(18.3-0)/2.35= 7.8 s
Part B
Givens again
Vi = 0 , Vf=41 mi/h = 18.3 m/s
t = 0.7
Use the first formula and substitute
a=(18.3-0)/0.7 = 26 m^2/s
Hope this helps