Answer:
3.9 seconds
Explanation:
Given:
y₀ = 55 m
y = 0 m
v₀ = 10 sin 30° m/s = 5 m/s
a = -9.8 m/s²
Find: t
y = y₀ + v₀ t + ½ at²
0 m = 55 m + (5 m/s) t + ½ (-9.8 m/s²) t²
0 = 55 + 5t − 4.9t²
4.9t² − 5t − 55 = 0
Solve with quadratic formula:
t = [ -(-5) ± √((-5)² − 4(4.9)(-55)) ] / 2(4.9)
t = (5 ± √1103) / 9.8
t = 3.9
