Answer:
6.7 seconds
Step-by-step explanation:
Let's calculate the maximum height covered by the object
Max height= U²Sin²tita/2g
Where g is acceleration due to gravity
Max height= 40²(sin90)²/(2*9.81)
Max height= 1600/19.62
Max height=81.55 m
Total max height= 30+81.55
Total max height= 111.55 m
Time t it will take to travel from the max height at acceleration of 4.9 m/s²
S= ut + ½at²
u= 0 at Mac height
S= 111.5 m
111.5 = ½(4.9)t²
223/4.9= t²
45.5= t²
6.745 seconds= t
6.7 seconds= t
