Answer:
0.229 seconds
Explanation:
Given:
y₀ = 80.6 m
v₀ = 0 m/s
a = -9.8 m/s²
We need to find the difference in times when y = 10.8 m and y = 2.10 m.
When y = 10.8 m:
y = y₀ + v₀ t + ½ at²
10.8 = 80.6 + (0) t + ½ (-9.8) t²
10.8 = 80.6 − 4.9 t²
4.9 t² = 69.8
t = 3.774
When y = 2.10 m:
y = y₀ + v₀ t + ½ at²
2.10 = 80.6 + (0) t + ½ (-9.8) t²
2.10 = 80.6 − 4.9 t²
4.9 t² = 78.5
t = 4.003
The difference is:
4.003 − 3.774 = 0.229
The man has 0.229 seconds to get out of the way.
