Answer:
104.9 m
5.63 s
45.3 m/s
Step-by-step explanation:
Given:
y₀ = 100 m
v₀ = 9.8 m/s
a = -9.8 m/s²
Find: y when v = 0 m/s
v² = v₀² + 2a (y − y₀)
(0 m/s)² = (9.8 m/s)² + 2 (-9.8 m/s²) (y − 100 m)
y = 104.9 m
Find: t when y = 0 m
y = y₀ + v₀ t + ½ at²
0 m = 100 m + (9.8 m/s) t + ½ (-9.8 m/s²) t²
0 = 100 + 9.8t − 4.9t²
t = [ -9.8 ± √(9.8² − 4(-4.9)(100)) ] / 2(-4.9)
t = (-9.8 ± 45.3) / -9.8
t = 5.63 s
Find: v when y = 0 m
v² = v₀² + 2a (y − y₀)
v² = (9.8 m/s)² + 2 (-9.8 m/s²) (0 m − 100 m)
v = -45.3 m/s
|v| = 45.3 m/s