Answer:
0.42 s, -4.1 m/s
Explanation:
The time it takes to reach 0.85 meters is the same as the time it takes to fall back to the ground.
y = y₀ + vt − ½ at²
0.85 m = 0 m + (0 m/s) t − ½ (-9.8 m/s²) t²
t = 0.42 s
It takes 0.42 seconds to reach the maximum height. So it takes another 0.42 seconds to land. Therefore, Laura is in the air for 0.84 seconds.
v² = v₀² + 2a (y − y₀)
v² = (0 m/s)² + 2(-9.8 m/s²) (0 m − 0.85 m)
v = -4.1 m/s
Laura hits the ground at a velocity of -4.1 m/s.
