Find the acceleration:
v² - u² = 2ax
(v = final velocity, u = initial velocity, a = acceleration, x = displacement)
(82.0 m/s)² - 0² = 2 a (0.400 m)
a = (82.0 m/s)² / (2 (0.400 m))
a = 8405 m/s²
Find the time:
x = ut + 1/2 at²
(t = time)
0.400 m = 0 + 1/2 (8405 m/s²) t²
t² = (0.400 m) / (1/2 (8405 m/s²))
t = √((0.400 m) / (1/2 (8405 m/s²)))
t ≈ 0.00976 s
