a. F = ma
F/a = ma/a
m = F/a
b. F = ma
-30 = -6a
a = 5
c. F = ma
30 = 10a
a = 3
Answer:
4x4x4 = 64 cubic ft
1 cubic foot = 7.48 gallons
64 x 7.48 = 478.72 gallons