Respuesta :
Answer:
t=1.58 seconds
Explanation:
The equation which models the height h of the seashell above water after t seconds
Height of seashell above water after t seconds; h = 40 - 8t²
Time that seashell is in air; t = 1.58 s
The sea shell is dropped under gravity and thus, from Newton's equations of motion, we know that height/distance is;
S = ut + ½gt²
Since it was dropped from a height and not the ground, then;
h = height of shell from ground
h_o = height from which the shell was dropped.
Thus, we have;
h - h_o = ut + ½gt²
We are told that the seashell was dropped into the ocean from a height of 40 ft. Thus;
h_o = 40 ft
It was dropped from rest and so; u = 0 ft/s
Acceleration due to gravity is; g = -32ft/s² (since it is free fall)
Thus;
h - 40 = 0(t) + ½(-32t²)
h = 40 - 8t²
The time that the seashell in the air will be after it has hit the surface which will be when h = 0.
Thus;
0 = 40 - 16t²
16t² = 40
t² = 40/16
t² = 2.5
t = √2.5
t = 1.58 s
Read more at; brainly.com/question/17576926