Answer:
a) 17.8m/s² b) 53.4m/s
Explanation:
write what you know and pick an equation
s = 80m
t = 3
u = 0
s = ut + 1/2at²
80 = 0 + 1/2 x a x 3²
80 = 1/2 x a x 9
1/2 a = 80/9
a = 17.777
a = 17.8 m/s²
now we can use v = u + at
v = 0 + 17.8 x 3
v = 53.4 m/s